Also, I've seen it occur when buffing someone with Longstrider. Literally, their portrait was fine, I cast Longstrider on them and the portrait was borked.
OK... this is truly odd... and would throw a wrench into the whole theory about this being solely related to re-spec/leveling/Magic Mirror-adjustments.
I will say that one difference between patch 7 and 8 I noticed is how long it takes to switch between characters when leveling up more than one of them. Before, I hadn't even noticed the "loading/busy" cursor at the bottom of the right side of the screen when going from one character to the next, but on patch 8, this can take a few seconds. That, perhaps, might have something to do with it too, but I can only speculate here. I don't think this ever happened to me when I only leveled a single character or when using the Mirror - in fact I don't think it *ever* happened with Tav at all. Seen it on SH, Karlach and Jaheira but never on Tav.
Such an occurance leads me to consider it might have something to do with applying effects to a character causing the portrait to have a chance to be changed to an invalid parameter and thus going to a "Default" setting. Of which "Leveling up" provides the most effects to a character and is thus more likely to cause an interaction.
Either way, the root cause would likely reside somewhere in the portrait parameter being affected by something other than the intended mechanisms (I.e. The character creation options you use when making a Tav/Durge/Hireling things like Wyll getting his horns or Shadowheart dying her hair)
That makes a lot of sense and would also explain why it, apparently, isn't "just" level ups and such that can cause this. Probably a slightly "deeper" issue than the level-up- or Mirror-screens/modes. The whole thing about probabilities would also explain the apparent randomness of this occurring. I've literally seen this happen (or not) on the exact same level up/re-spec with no obvious differences between what I did from one level up to the next.
