In my experience when Alarm.com rules don’t work, the problem usually (maybe always) occurs when the rules are being sent down from Alarm.com to the 2GIG panel to be saved. I don’t know why but sometimes they don’t get saved in 2GIG properly. It seems to happen most when one creates or modifies multiple rules in a short period of time. The higher the rate of changes the more likely the problem occurs. It’s almost as if they can collide with each other when being saved. One thing I like to do is test all (even existing) rules after making significant changes. Also, if possible, wait a few minutes between saving rule changes… although sometimes I don’t have the patience for that.
Even if you didn’t create or modify that rule yourself recently, it’s possible that while troubleshooting your Schlage lock the rules were deleted and then re-added. Some trouble-shooting maintenance operations done remotely will cause rules to be deleted and then re-added.
I’m just guessing here. Obviously I don’t know exactly what would have caused this particular rule not to work. Did you try/do anything to resolve this problem or did it just seem to resolve itself?