This is related to the Ritn set of mods that you have installed for swapping characters. There's a weird interaction between the characters and forces which only happens when those mods are loaded. It's not the code that this mod is running that spills the inventory, it's likely some interesting out-of-order expectations in the game, that mod, or this mod. When that mod is installed, it listens/reacts to quite a few of the same events for forces, players, and surfaces, so there's much more going on when the character transitions. I'm not really sure what I could do about it, unfortunately.