1. Are you doing anything slightly unusual in that Begin Step event, like having a local variable named "ia_combat" (strange question, but I can't think of anything else that'd throw it off)
2. If you copy just the macros-script and the object into a separate project (commenting out/replacing with an empty script call anything referencing game-specific things), does the issue persist there?
I'd message you on Twitter but you have direct messages closed to those that you don't follow.