I don't know if this is a bug or if I am really dumb. I am trying to cast "Magic Trap" on pouches in my inventory and I am getting the following error message "You can't trap that". I have tried to cast on multiple types of containers, some in my inventory, some on the ground, etc. Same message.
Thank you so much for the reply. I just tried it again on an un-opened pouch in my inventory, and it gave me the same message "You can't trap that". However, it DID work on a crate in my inventory (as you suggested). So I guess only certain containers can be trapped. Thanks again for helping me out.