From
this thread (by Larian):
"We continue to look at your feedback, and are preparing additional hotfixes for issues you’ve reported. This includes an issue with shared items when dismissing companions, which we are aware of and looking into."
Sweet. I will however keep complaining about how shitty the stared stash is until it is fixed. This was a horrible way to implement a shared stash and the fact that they just threw it in all willy nilly without, at minimum, an option to turn it off is just dumb.