diff --git a/scp.c b/scp.c
index e06ab8d0..3fa9b8a9 100644
--- a/scp.c
+++ b/scp.c
@@ -4941,12 +4941,12 @@ else {
             return sim_messagef (SCPE_ARG, "Invalid argument: %s\n", gbuf);
         }
     }
-if (cond == SCPE_OK)
-    return sim_messagef (SCPE_ARG, "Invalid argument: %s\n", gbuf);
 if ((NULL == cptr) || ('\0' == *cptr)) {                /* Empty Action */
     free(sim_on_actions[sim_do_depth][cond]);           /* Clear existing condition */
     sim_on_actions[sim_do_depth][cond] = NULL; }
 else {
+    if ((cptr > sim_sub_instr_buf) && ((size_t)(cptr - sim_sub_instr_buf) < sim_sub_instr_size))
+        cptr = &sim_sub_instr[sim_sub_instr_off[cptr - sim_sub_instr_buf]]; /* get un-substituted string */
     sim_on_actions[sim_do_depth][cond] = 
         (char *)realloc(sim_on_actions[sim_do_depth][cond], 1+strlen(cptr));
     strcpy(sim_on_actions[sim_do_depth][cond], cptr);