Apparently, every time I load a save my characters swap their weapons (from melee to ranged and back).
I was rather confused because Lae'zel was suddenly running around with her bow out and not her starting long sword on the nautiloid. It doesn't even have to be a character's turn or for them even to be in your party. I left Shadowheart at camp with her mace and shield equipped, had saved and reloaded, popped back in to grab her for a run in the crypts and, surprise! She has a crossbow on her back. I even got to watch Gale examining his mirror image, one with a quarterstaff and one with a crossbow.
It happens every time I reload. And it seems to happen with people not in the party as well. At the battle at the druid gate, the mercenary who usually uses a bow ended up swapping to her bare fists.
To be fair, I am using a drow druid that I made with the new patch and not with the hotfix. Don't know if that changes anything.
It's been doing this for me as well, and it's really annoying. Every time I load a game, I have to switch everyone back. And it did it for me both with a character created just before the hotfix and one created after, so I don't think that impacts it. I didn't actually notice it doing with anyone outside of my party members or camp members, but that might have just been me being unobservant.