This may be a more serious bug than thought. I have a tankless water heater that I monitor power with a Aeotec smart plug. It has got right at or below freezing this last couple of mornings and usually that means the Heat strips come on in the tank. I have a rule that monitors this and whenever the heat strips come on I get a pushover message. I just realized this morning I have gotten no message.
I opened the rule, and it looked as shown in the OPs example all rules showed as unused even though they are, and after opening the action page and closing it everything looked normal. This is only antidotal at this point as I had no logging active for the rule, but this is an old rule that has been functioning for a long time. It, as you mentioned, had not been opened in a long time.
I can tell the heat strips did come on because I also monitor the Tankless's energy usage and cost. I can see from the device page that the heat strips did come on this morning. It normally pulls about 20 or 30 watts when the water heater is running, but early this morning when no one was up it was pulling over 100.
So it appears that the rule was not running until I opened it and cleared the unused flag.
