I've encountered some weird bug when I loaded a quicksave. I was playing with four characters, but the character portraits of 3 of the 4 characters are now doubled so that all my 6 character slots in my UI are full with only these three. The corresponding quick keys were also bound to only the 3 characters. I can only select my 4th character manually now.

Did I press some key? I can't find people with the same issue online...