New Form

I'm finding that form rules are working very inconsistently. I've added some very simple rules that seem to stop working for no apparent reason after revisiting the rules settings and saving the form. One with two conditions - A and B. I set up the rule with A and it works. I set it up with B and it works. I set it up with A and B and it works. I then added a completely different rule and the first one stopped working. I've spent over an hour trying to get a few rules to work and it's very frustrating, especially with no way to troubleshoot ... all I can do is start again.