Got it! Thanks for pointing this out and bearing with the hassle of sending the save, this would have been a tricky one to find otherwise. Turns out the code I was using to swap the clip status was only present on some of the screens. I've since moved on to a better method of equipment detection (that's universal, so this kind of thing can't happen) so I took the opportunity to swap the clip detection to the new system. I'll probably wait to release a new version until I have a few more bugs/tuneups I can bundle together, but you can get the patched version here if you'd like to test it. Bugged saves can be fixed just by toggling the clips on and off. Their equipped status should match their status in battle after that.
Defend/Guard isn't especially useful at the moment, no (except for intentionally stalling). Traditionally it would be used to counter heavy attacks you could anticipate, but that's served by Flash Dodge. Having some energy regen tied to it is an interesting idea; might be less frustrating and flow better than the separate Focus skill. I'll have to consider. And yes, MV's random number handling is frustrating in general. I've build in a lot of failsafes to force a failure or success after a point to counter it, but nothing on resist yet. May be worth adding a counter there too, so you win say your fourth attempt by default.