this sounds interesting. My only idea is that there was probably an issue with one property/rule that worked due to a bug that has been fixed or a behaviour that has been changed.
I have not heard abotu such issues before - if you are interested to find out what exactly happened I think it sould be beneficial to have a Service Request filed for this. we would need a Feedback and the old version and maybe some guidance how the rule looked before it has been changed to work again. Then we can set this up and give it a try.