This happens to me at least once a week. It seems random and inconsistent, so it's hard to reproduce, but this last time I believe I was working within a group in isolation mode, then after exiting isolation mode and selecting items in a different group, the bounding box "stuck" to always including the last item selected within the previous group. I use groups a lot and move in and out of isolation mode frequently, so this may be why I experience this bug so often. I was unsuccessful in trying to reproduce it. To remedy, I just quit and restart Illustrator.
This happens to me at least once a week. It seems random and inconsistent, so it's hard to reproduce, but this last time I believe I was working within a group in isolation mode, then after exiting isolation mode and selecting items in a different group, the bounding box "stuck" to always including the last item selected within the previous group. I use groups a lot and move in and out of isolation mode frequently, so this may be why I experience this bug so often. I was unsuccessful in trying to reproduce it. To remedy, I just quit and restart Illustrator.