Bug #1 Force Field tends to disappear from your hand if you are struck before you apply it. I was hit with Fiery Stab, no traits attached, and bang! my Force Field dropped from my hand. The log said nothing about it being discarded (It was not in play, it was in my hand). This has happened several times as of late. Bug #2 Targeting has become a real issue in qcb. Accidentally targeting your toons happens all too often. Why is it you can click both the tile and/or the toon. It should just be the tile regardless of the kind of attack or buff. Depending on what races/classes/skin you are using it can become almost impossible to target particular adjacent tiles.
I suspect there has to be something else going on for this to happen. Could radiation (monster version) or Dastardly Curse have been in play? In any case, opening the console (F2 to open, F1 to close), and copying and posting the battle data would certainly help track it down. Tiles must be selected for things that target tiles. Characters must be selected for things that target characters. There is still a bug that prevents small figures occludud by large figures (spider hidden by tree) from being targeted, but I'm not sure if that's what you're referring to.
As I stated, no traits were attached. Elf warrior with zero traits, debuffs, curses, or anything of the like.