App keeps losing its subscription to events and thus stops triggering

[Alan_F]

To be a bit more precise, the rule doesn't unsubscribe when PB is false. The rule unsubscribes when the required expression is false. In your case those two are equivalent, but any false required expression should remove the subscriptions.

I don't see your rule actions, but something must be stopping the rule between when you set the PB false and when you set it true again.

From another post:

@bravenel

Another significant advantage of Required Expression (when there is not a trigger overlap as just described), is that when the Required Expression becomes false, the triggers of the rule are unsubscribed / unscheduled. The rule will have subscriptions to events or schedules that might change the Required Expression state, but not subscriptions to the triggers. I have some shades that open and close daily between April and August only. So after a specific date in August, that rule is completely quiescent until April, when it will awake from a scheduled job to begin its daily routine.