There have been some items that I have tried to combine inside my inventory only for the prompt to not work. sometimes I'm able to solve the problem by removing the item from my inventory to the vicinity and then combining it with the other item in my hands, which can be tedious.

Additionally, when I have tried to combine the duct tape with a damaged item to repair it I ended up restraining my hands instead. It seemed the prompt did not work here as intended either.