Totally agree, the game is fantastic and knowing it's such a small group puts all the little things aside.. You can feel the love.
I had that bug a few times too. I have no idea where or how to fix. I wish I did. I checked a few of the abilities "targets" code and they all seem to have the right number. It always happened on boss fights for me and when I really needed a heal, but that added an unexpected wrincle.
There is a shield, the Magistral Crest, that has a "low chance of reflecting magic" on my first playthrough I used it a lot after the Wizard shield. On my next play, I never used it and haven't had the bug. Maybe nothing, maybe not. It might be possible that it applies the reflect code permanently to the character, but I have no other explanation.
Lots of enemies have high evasion, especially the fliers and the "ghost" or "black fingers" ones. I'm making a pass on the classes hit/crit/evasion and might bump the fighters a point or 2.