diff -up lua-5.4.3/src/lvm.c.bug3 lua-5.4.3/src/lvm.c
--- lua-5.4.3/src/lvm.c.bug3	2021-04-28 13:27:54.025590350 -0400
+++ lua-5.4.3/src/lvm.c	2021-04-28 13:28:55.233614835 -0400
@@ -847,10 +847,19 @@ void luaV_finishOp (lua_State *L) {
       luaV_concat(L, total);  /* concat them (may yield again) */
       break;
     }
-    case OP_CLOSE:  case OP_RETURN: {  /* yielded closing variables */
+    case OP_CLOSE: {  /* yielded closing variables */
       ci->u.l.savedpc--;  /* repeat instruction to close other vars. */
       break;
     }
+    case OP_RETURN: {  /* yielded closing variables */
+      StkId ra = base + GETARG_A(inst);
+      /* correct top to signal correct number of returns (in case the
+         return is "in top" */
+      L->top = ra + ci->u2.nres;
+      /* repeat instruction to close other vars. and complete the return */
+      ci->u.l.savedpc--;
+      break;
+    }
     default: {
       /* only these other opcodes can yield */
       lua_assert(op == OP_TFORCALL || op == OP_CALL ||
@@ -1670,6 +1679,7 @@ void luaV_execute (lua_State *L, CallInf
           n = cast_int(L->top - ra);  /* get what is available */
         savepc(ci);
         if (TESTARG_k(i)) {  /* may there be open upvalues? */
+          ci->u2.nres = n;  /* save number of returns */
           if (L->top < ci->top)
             L->top = ci->top;
           luaF_close(L, base, CLOSEKTOP, 1);