formula for action with "Custom expression" not updated after condition deletion - Breaks action

1) Create trigger action with a custom expression such as "A and (B or C or D or E) and F and G and H and I" where B, C, D, and E are templates.

2) Delete template referenced by D

Custom expression does not get automatically updated. That action will now fire for a variety of events that have nothing to do with the trigger. One must find and update the custom expression manually to get the action to quit firing.