Possible sleigh misrepresentation for indirect memory operations

[Wall-AF]

Is there a bug/missing/incorrect sleigh specifications here?

In the assembly statement below, the address from which the register (AX) is populated is recognised as a member of the global structure (defined at location DS:9e86 of length 0x47a bytes):

Address DS:a2dc = g_Obj0x47a_DS_9e86.nElemsIn0x472And0x476_0x456

11a0:1511 a1 dc a2           MOV AX,DS:[g_Obj0x47a_DS_9e86.nElemsIn0x472And0x476_0x456]
Constructor Line #'s:
   MOV(ia.sinc:3074), moffs16(ia.sinc:930), seg16(ia.sinc:767)

3074	:MOV AX,moffs16        is vexMode=0 & opsize=0 & byte=0xa1; AX & moffs16 { AX=moffs16; }
930	moffs16: seg16^[imm16] is addrsize=0 & seg16 & imm16 { tmp:$(SIZE) = segment(seg16,imm16:2); export *:2 tmp; }
767	seg16: DS:             is segover=0 & DS	     { export DS; }

Whereas in the following assembly (which uses a more complex statement) the address 0xa0ac isn't converted into the structures field it represents:

Address DS:a0ac = g_Obj0x47a_DS_9e86.field20_0x226

11a0:1547 8a 87 ac a0        MOV AL,byte ptr DS:[BX + 0xa0ac]
Constructor Line #'s:
   MOV(ia.sinc:3065), rm8(ia.sinc:986), Mem(ia.sinc:785), Mem16(ia.sinc:783),
   seg16(ia.sinc:767), addr16(ia.sinc:703), Reg8(ia.sinc:629)

3065	:MOV Reg8,rm8         is vexMode=0 & byte=0x8a; rm8 & Reg8 ... { Reg8 = rm8; }
986	rm8: "byte ptr" Mem   is Mem                                   { export *:1 Mem; }
785	Mem: Mem16            is addrsize=0 & Mem16                    { export Mem16; }
767	seg16: DS:            is segover=0 & DS	                       { export DS; }
703	addr16: [BX + imm16]  is mod=2 & r_m=7 & BX; imm16             { local tmp=BX+imm16; export tmp; }
629	Reg8:   reg8          is reg8                                  { export reg8; }

It should be:
11a0:1547 8a 87 ac a0 MOV AL,byte ptr DS:[BX + g_Obj0x47a_DS_9e86.field20_0x226]

I've noticed elsewhere that if the MOV statement just uses the indirection [BX] and BX is the result of what seems an arbitrary complex address calculation, the structures' field is shown.

Could this also be a reason for #5720 (comment)?