I would use the bug report tool, but like many other things in this game, it’s broken for me also.
When thralls with bows switch to melee weapons, they don’t put the bow away, so they end up having both weapons out. So far this is with bow/katana combo, haven’t tested this with other weapons, but then again- it’s not my job to. All I know is, when it happens, a random gruel that wasn’t there before shows up in their inventory.
I’m not really expecting anything to be done about this as that is the way things go, but I had to at least say something in the event that the people in charge of fixing bugs were replaced by others that are willing to do the work.
No need for screen shots, just picture a thrall with a bow on their back, and a bow in their hand simultaneously. And if they use a melee weapon, the bow remains in their hand. Much like the arrow in the hand bug that you never bothered to fix for several years.