diff --git a/NEWS b/NEWS
index a6c2445e7e67..daf09f9d3699 100644
--- a/NEWS
+++ b/NEWS
@@ -10,6 +10,10 @@ Any uppercase BUG_* names are modernish shell bug IDs.
   the last component command was an external command and the pipeline was
   the last command in a background subshell.
 
+- When any trap except DEBUG, KILL or STOP is set to a non-empty command,
+  the last command in a script or forked subshell will no longer avoid forking
+  before executing; this optimization incorrectly bypassed the traps.
+
 2022-06-15:
 
 - Fixed a bug where converting an indexed array into an associative array in
diff --git a/src/cmd/ksh93/bltins/trap.c b/src/cmd/ksh93/bltins/trap.c
index 76e134de8f69..493aa5a2f928 100644
--- a/src/cmd/ksh93/bltins/trap.c
+++ b/src/cmd/ksh93/bltins/trap.c
@@ -136,13 +136,6 @@ int	b_trap(int argc,char *argv[],Shbltin_t *context)
 						sh.trapnote = 0;
 
 				}
-				if(sig == SH_ERRTRAP)
-				{
-					if(clear)
-						sh.errtrap = 0;
-					else if(!sh.fn_depth || sh.end_fn)
-						sh.errtrap = 1;
-				}
 				continue;
 			}
 			if(sig > sh.sigmax)
@@ -159,8 +152,6 @@ int	b_trap(int argc,char *argv[],Shbltin_t *context)
 			else if(clear)
 			{
 				sh_sigclear(sig);
-				if(sig == 0)
-					sh.exittrap = 0;
 				if(dflag)
 					signal(sig,SIG_DFL);
 			}
@@ -180,8 +171,39 @@ int	b_trap(int argc,char *argv[],Shbltin_t *context)
 				sh.st.trapcom[sig] = (sh.sigflag[sig]&SH_SIGOFF) ? Empty : sh_strdup(action);
 				if(arg && arg != Empty)
 					free(arg);
-				if(sig == 0 && (!sh.fn_depth || sh.end_fn))
-					sh.exittrap = 1;
+			}
+		}
+		/*
+		 * Set a flag for sh_exec() to disable exec-without-fork optimizations if any trap is set and non-empty.
+		 * (In ksh functions, there may be parent scope traps, so do not reset to 0 if in a ksh function.)
+		 */
+		if(sh.fn_depth==0)
+			sh.st.trapdontexec = 0;
+		if(!sh.st.trapdontexec)
+		{
+			/* EXIT and real signals */
+			for(sig=0; sig<=sh.sigmax; sig++)
+			{
+				/* these cannot be trapped */
+				if(sig==SIGKILL || sig==SIGSTOP)
+					continue;
+				if(sh.st.trapcom[sig] && *sh.st.trapcom[sig])
+				{
+					sh.st.trapdontexec++;
+					break;
+				}
+			}
+		}
+		if(!sh.st.trapdontexec)
+		{
+			/* other pseudosignals -- exclude DEBUG as it is executed before the command */
+			for(sig=0; sig<SH_DEBUGTRAP; sig++)
+			{
+				if(sh.st.trap[sig] && *sh.st.trap[sig])
+				{
+					sh.st.trapdontexec++;
+					break;
+				}
 			}
 		}
 	}
diff --git a/src/cmd/ksh93/include/shell.h b/src/cmd/ksh93/include/shell.h
index 020152c5f6b0..5214e04e30b0 100644
--- a/src/cmd/ksh93/include/shell.h
+++ b/src/cmd/ksh93/include/shell.h
@@ -204,6 +204,7 @@ struct sh_scoped
 	short		opterror;
 	int		ioset;
 	unsigned short	trapmax;
+	char		trapdontexec;	/* stop exec optimization if any non-DEBUG/SIGKILL/SIGSTOP trap is set and non-empty */
 	char		*trap[SH_DEBUGTRAP+1];
 	char		**otrap;
 	char		**trapcom;
@@ -335,9 +336,9 @@ struct Shell_s
 	int		inuse_bits;
 	struct argnod	*envlist;
 	struct dolnod	*arglist;
-	int		fn_depth;
+	int		fn_depth;	/* scoped ksh-style function call depth */
 	int		fn_reset;
-	int		dot_depth;
+	int		dot_depth;	/* dot-script and POSIX function call depth */
 	int		hist_depth;
 	int		xargmin;
 	int		xargmax;
@@ -381,9 +382,6 @@ struct Shell_s
 	char		*mathnodes;
 	char		*bltin_dir;
 	struct Regress_s*regress;
-	char 		exittrap;
-	char 		errtrap;
-	char 		end_fn;
 #if SHOPT_FILESCAN
 	char		*cur_line;
 #endif
diff --git a/src/cmd/ksh93/sh/fault.c b/src/cmd/ksh93/sh/fault.c
index b1b73e9a9e60..27c03f734f20 100644
--- a/src/cmd/ksh93/sh/fault.c
+++ b/src/cmd/ksh93/sh/fault.c
@@ -315,11 +315,17 @@ void	sh_sigdone(void)
  * Restore to default signals
  * Free the trap strings if mode is non-zero
  * If mode>1 then ignored traps cause signal to be ignored 
+ * If mode==-1 we're entering a new function scope in sh_funscope()
  */
 void	sh_sigreset(register int mode)
 {
 	register char	*trap;
 	register int 	flag, sig=sh.st.trapmax;
+	/* do not reset sh.st.trapdontexec in a new ksh function scope as parent traps will still be active */
+	if(mode < 0)
+		mode = 0;
+	else
+		sh.st.trapdontexec = 0;
 	while(sig-- > 0)
 	{
 		if(trap=sh.st.trapcom[sig])
diff --git a/src/cmd/ksh93/sh/init.c b/src/cmd/ksh93/sh/init.c
index 6e4ed78e8ee5..fb84480ecd3b 100644
--- a/src/cmd/ksh93/sh/init.c
+++ b/src/cmd/ksh93/sh/init.c
@@ -1527,9 +1527,6 @@ Shell_t *sh_init(register int argc,register char *argv[], Shinit_f userinit)
 	astintercept(&sh.bltindata,1);
 	if(sh.userinit=userinit)
 		(*userinit)(&sh, 0);
-	sh.exittrap = 0;
-	sh.errtrap = 0;
-	sh.end_fn = 0;
 	error_info.exit = sh_exit;
 #ifdef BUILD_DTKSH
 	{
@@ -1714,9 +1711,6 @@ int sh_reinit(char *argv[])
 	sh.inpipe = sh.outpipe = 0;
 	job_clear();
 	job.in_critical = 0;
-	sh.exittrap = 0;
-	sh.errtrap = 0;
-	sh.end_fn = 0;
 	/* update ${.sh.pid}, $$, $PPID */
 	sh.ppid = sh.current_pid;
 	sh.current_pid = sh.pid = getpid();
diff --git a/src/cmd/ksh93/sh/main.c b/src/cmd/ksh93/sh/main.c
index 0f6210e22708..8f43b418818a 100644
--- a/src/cmd/ksh93/sh/main.c
+++ b/src/cmd/ksh93/sh/main.c
@@ -467,9 +467,6 @@ static void	exfile(register Sfio_t *iop,register int fno)
 	error_info.line = 1;
 	sh.inlineno = 1;
 	sh.binscript = 0;
-	sh.exittrap = 0;
-	sh.errtrap = 0;
-	sh.end_fn = 0;
 	if(sfeof(iop))
 		goto eof_or_error;
 	/* command loop */
diff --git a/src/cmd/ksh93/sh/xec.c b/src/cmd/ksh93/sh/xec.c
index a7f093c151b9..d2707d9cb83a 100644
--- a/src/cmd/ksh93/sh/xec.c
+++ b/src/cmd/ksh93/sh/xec.c
@@ -909,10 +909,17 @@ static Namval_t *enter_namespace(Namval_t *nsp)
 /*
  * Check whether to execve(2) the final command or make its redirections permanent.
  */
-static int check_exec_optimization(struct ionod *iop)
+static int check_exec_optimization(int type, int execflg, int execflg2, struct ionod *iop)
 {
-	if(sh.subshell || sh.exittrap || sh.errtrap)
+	if(type&(FAMP|FPOU)
+	|| !(execflg && sh.fn_depth==0 || execflg2)
+	|| sh.st.trapdontexec
+	|| sh.subshell
+	|| ((struct checkpt*)sh.jmplist)->mode==SH_JMPEVAL
+	|| (pipejob && (sh_isstate(SH_MONITOR) || sh_isoption(SH_PIPEFAIL) || sh_isstate(SH_TIMING))))
+	{
 		return(0);
+	}
 	/* '<>;' (IOREWRITE) redirections are incompatible with exec */
 	while(iop && !(iop->iofile & IOREWRITE))
 		iop = iop->ionxt;
@@ -1133,7 +1140,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 				int tflags = 1;
 				if(np && nv_isattr(np,BLT_DCL))
 					tflags |= 2;
-				if(execflg && !check_exec_optimization(io))
+				if(execflg && !check_exec_optimization(type,execflg,execflg2,io))
 					execflg = 0;
 				if(argn==0)
 				{
@@ -1506,15 +1513,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			int pipes[3];
 			if(sh.subshell)
 				sh_subtmpfile();
-			no_fork = !(type&(FAMP|FPOU))
-			&& !sh.subshell
-			&& !(sh.st.trapcom[SIGINT] && *sh.st.trapcom[SIGINT])
-			&& !sh.st.trapcom[0]
-			&& !sh.st.trap[SH_ERRTRAP]
-			&& ((struct checkpt*)sh.jmplist)->mode!=SH_JMPEVAL
-			&& (execflg && sh.fn_depth==0 || execflg2)
-			&& !(pipejob && (sh_isstate(SH_MONITOR) || sh_isoption(SH_PIPEFAIL) || sh_isstate(SH_TIMING)));
-			if(no_fork)
+			if(no_fork = check_exec_optimization(type,execflg,execflg2,t->fork.forkio))
 				job.parent=parent=0;
 			else
 			{
@@ -1799,7 +1798,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			jmpval = sigsetjmp(buffp->buff,0);
 			if(jmpval==0)
 			{
-				if(execflg && !check_exec_optimization(t->fork.forkio))
+				if(execflg && !check_exec_optimization(type,execflg,execflg2,t->fork.forkio))
 				{
 					execflg = 0;
 					flags &= ~sh_state(SH_NOFORK);
@@ -3100,7 +3099,7 @@ int sh_funscope(int argn, char *argv[],int(*fun)(void*),void *arg,int execflg)
 	}
 	if(!fun && sh_isoption(SH_FUNCTRACE) && sh.st.trap[SH_DEBUGTRAP] && *sh.st.trap[SH_DEBUGTRAP])
 		save_debugtrap = sh_strdup(sh.st.trap[SH_DEBUGTRAP]);
-	sh_sigreset(0);
+	sh_sigreset(-1);
 	if(save_debugtrap)
 		sh.st.trap[SH_DEBUGTRAP] = save_debugtrap;
 	argsav = sh_argnew(argv,&saveargfor);
@@ -3117,8 +3116,6 @@ int sh_funscope(int argn, char *argv[],int(*fun)(void*),void *arg,int execflg)
 		nv_putval(SH_PATHNAMENOD,sh.st.filename,NV_NOFREE);
 		nv_putval(SH_FUNNAMENOD,sh.st.funname,NV_NOFREE);
 	}
-	if((execflg & sh_state(SH_NOFORK)))
-		sh.end_fn = 1;
 	jmpval = sigsetjmp(buffp->buff,0);
 	if(jmpval == 0)
 	{
@@ -3169,7 +3166,6 @@ int sh_funscope(int argn, char *argv[],int(*fun)(void*),void *arg,int execflg)
 	sh.st = *prevscope;
 	sh.topscope = (Shscope_t*)prevscope;
 	nv_getval(sh_scoped(IFSNOD));
-	sh.end_fn = 0;
 	if(nsig)
 	{
 		for (isig = 0; isig < nsig; ++isig)
diff --git a/src/cmd/ksh93/tests/basic.sh b/src/cmd/ksh93/tests/basic.sh
index 31fb6336d135..59449651db39 100755
--- a/src/cmd/ksh93/tests/basic.sh
+++ b/src/cmd/ksh93/tests/basic.sh
@@ -928,8 +928,10 @@ AIX | SunOS)
 esac
 
 # ======
+# Test exec optimization of last command in script or subshell
+
 (
-	ulimit -t unlimited 2>/dev/null
+	ulimit -t unlimited 2>/dev/null  # fork subshell
 	print "${.sh.pid:-$("$SHELL" -c 'echo "$PPID"')}"  # fallback for pre-93u+m ksh without ${.sh.pid}
 	"$SHELL" -c 'print "$$"'
 ) >out
@@ -937,5 +939,66 @@ pid1= pid2=
 { read pid1 && read pid2; } <out && let "pid1 == pid2" \
 || err_exit "last command in forked subshell not exec-optimized ($pid1 != $pid2)"
 
+got=$(
+	ulimit -t unlimited 2>/dev/null  # fork subshell
+	print "${.sh.pid:-$("$SHELL" -c 'echo "$PPID"')}"  # fallback for pre-93u+m ksh without ${.sh.pid}
+	"$SHELL" -c 'print "$$"'
+)
+pid1= pid2=
+{ read pid1 && read pid2; } <<<$got && let "pid1 == pid2" \
+|| err_exit "last command in forked comsub not exec-optimized ($pid1 != $pid2)"
+
+cat >script <<\EOF
+echo $$
+sh -c 'echo $$'
+EOF
+"$SHELL" script >out
+pid1= pid2=
+{ read pid1 && read pid2; } <out && let "pid1 == pid2" \
+|| err_exit "last command in script not exec-optimized ($pid1 != $pid2)"
+
+for sig in EXIT ERR ${ kill -l; }
+do
+	case $sig in
+	KILL | STOP)
+		# cannot be trapped
+		continue ;;
+	esac
+
+	# the following is tested in a background subshell because ksh before 2022-06-18 didn't
+	# do exec optimization on the last external command in a forked non-background subshell
+	(
+		trap + "$sig"  # unadvertised (still sort of broken) feature: unignore signal
+		trap : "$sig"
+		print "${.sh.pid:-$("$SHELL" -c 'echo "$PPID"')}"  # fallback for pre-93u+m ksh without ${.sh.pid}
+		"$SHELL" -c 'print "$$"'
+	) >out &
+	wait
+	pid1= pid2=
+	{ read pid1 && read pid2; } <out && let "pid1 != pid2" \
+	|| err_exit "last command in forked subshell exec-optimized in spite of $sig trap ($pid1 == $pid2)"
+
+	got=$(
+		ulimit -t unlimited 2>/dev/null  # fork subshell
+		trap + "$sig"  # unadvertised (still sort of broken) feature: unignore signal
+		trap : "$sig"
+		print "${.sh.pid:-$("$SHELL" -c 'echo "$PPID"')}"  # fallback for pre-93u+m ksh without ${.sh.pid}
+		"$SHELL" -c 'print "$$"'
+	)
+	pid1= pid2=
+	{ read pid1 && read pid2; } <<<$got && let "pid1 != pid2" \
+	|| err_exit "last command in forked comsub exec-optimized in spite of $sig trap ($pid1 == $pid2)"
+
+	cat >script <<-EOF
+	trap ":" $sig
+	echo \$\$
+	sh -c 'echo \$\$'
+	EOF
+	"$SHELL" script >out
+	pid1= pid2=
+	{ read pid1 && read pid2; } <out && let "pid1 != pid2" \
+	|| err_exit "last command in script exec-optimized in spite of $sig trap ($pid1 == $pid2)"
+done
+
 # ======
 exit $((Errors<125?Errors:125))