Yeah I've noticed some odd things happening when looting too.
Went to pick up a polearm (2slot maaybe 3), had my current polearm out (1 slot).
I end up holding the new polearm AND the first one...while all my throwing weapons (2 slot spears and 1 slot daggers) were dumped on the ground.
Not only that but only the throwing spears actually landed on the ground, the throwing daggers had vanished so I couldn't get them back once I realised I'd made a mistake.