it's probably a bug, I've had it happen at random times with random characters. For the most part you have to have lockpicks (they only work to unlock things) and a disarm kit (to disarm things only) It may be you have the lockpick ones, vs. having the disarm kit. Once you fail the kit is gone and unless you have another one then the selection will either be greyed out, or not show up. Can't remember which. Some chests will pop a perception check when you unlock them, there is a reason for it. be wary if this happens.
