Email filter problem after update

I'm new to the community and don't really know how things work, so maybe this is the wrong place for this. I had a seemingly catastrophic problem after updating yesterday. All of the emails sitting in my inbox disappeared, and were gone from the yahoo server as well. Long story short, I figured out what happened. In my filter rules I sometimes had a blank entry at the end of the list. Previously that had been ignored, but after the update it is now treated as a match. So the first filter that had a blank in it caused everything in my inbox to be moved to a certain folder in my Local Folders. Obviously, it would be legitimate to not allow blank entries in the filters, but once you've allowed it, you really shouldn't make a change. In the end the solution was simple, but it wasted a fair portion of my day figuring it out.