diff --git a/radix-engine/src/engine/interpreters/scrypto_interpreter.rs b/radix-engine/src/engine/interpreters/scrypto_interpreter.rs
index 604820408c1..0eed1df2305 100644
--- a/radix-engine/src/engine/interpreters/scrypto_interpreter.rs
+++ b/radix-engine/src/engine/interpreters/scrypto_interpreter.rs
@@ -116,8 +116,8 @@ mod tests {
         // RFC 2056
         fn assert_all() {
             assert_send::<ScryptoInterpreter<DefaultWasmEngine>>();
-            // TODO: make sure engine is multi-thread safe!
-            // assert_sync::<ScryptoInterpreter<DefaultWasmEngine>>();
+            // TODO: make sure engine is indeed multi-thread safe!
+            assert_sync::<ScryptoInterpreter<DefaultWasmEngine>>();
         }
     };
 }