Actually just found out it's in the script itself. :guffaw:
BUT I also found out it is not a problem in the end at all, since the only way you can have this crash is by:
Having your Player Starting Position in a map with a chest, getting the chest, pressing F12, then start a new game (therefore, in the same map) and go to get the chest again.
He used to have the same problem with save games but he fixed it :
You save in map X, take the chest, load the save game file in map X and get the chest again. And this was fixed by Napoleon :)
The logic on both examples is the same, but the save file one was fixed, the starting position one was not :D
So technically, the problem exists, but doesn't bother anyone unless you do what I did in the first example (which is pretty rare to happen and is easily avoidable, just don't put a chest in the first map lol).