Charles is probably right on with regards to lots of changes.
I do a fair amount of changes for tests, and there was one bizarre anomaly I experienced:
I had a macro that did a few things, and in the middle of it it was to turn ON a light. Everytime I ran it, everything worked as expected but that light would not turn ON (and it was controllable through the AHP graphic switch); I double & triple checked my macro and the command shown was correct to turn that light ON.
I cleared the interface, reloaded, same thing. I looked at the Activity Monitor while it was running, and I was surprised to see it was sending out an OFF command when the shown command was to send an ON.
I had to delete that command, save the file, re-inset that command again, save the file, clear interface & download.
Without the activity monitor, I would have never known that the graphic was showing a false command state. So if things don't work as expected, don't believe everything you see... check the activity monitor.