Maybe you casted the chest, but forgot to "take it back" when leaving the location. When going out of location, chest doesn't return automatically to the caster inventory, but stays where it was casted in. And if in other location You tried to cast it again, you would get only a disrupted spell animation, without any additional info. Once I left the chest somewhere on the 1st level of the Temple, and had to return for it all the way from Hommlet.
I didn't forget it and even tried to return to the location repeatedly. I'm a big fan of D&D so it is a minor issue for me because rest of the game is very good.
Same thing here. It was working fine for a little while and then right when I had a big stack of dead guys with armor to load up, no chest available. I agree also, a very minor issue since it was really a mini-cheat to let me carry more loot!
Having fun with the game though. Up to level 5 and my crew still gets demolished if I'm not real careful. (The web spell is my new best friend.) Definitely takes me back to my pen and paper days...