My buddy is experiencing multiple crashes when loading (join, load savegame) in some cases.
We managed to reproduce the crash by taking the ornate chest that's near the Twins-by-fire-joined and storing it in my inventory. If I quicksave/quickload, he crashes 100% of the time. Loading the savegame just before taking the chest is fine. The chest doesn't have a tooltip when pressing ALT. Maybe the inventory gets corrupted and he can't load it?
Edit: After further research with different chests and different characters, it seems the issue is related to characters being encumbered.
Link to savegame in question
https://www.dropbox.com/s/9oy6q56byrh4h3y/pickupchestandcooppartnercrashesonload.zip?dl=0