It's not normal for them to work loose naturally, as they use loctite to lock the threads in the factory. However, I notice yours is not new, so its possible that someone has tightened or loosened them and broken the thread locker - you'll probably never know!
Either way, I would personally pick up the tools as I do like to tinker. I received a brand new TTi the other day and immediately tightened the threads on one of the handles as I prefer my tools that way but I'm sure the warranty would fix them up for you if you preferred!