Wanted to ask, did this just start happening or was the gun given to someone to look at and then this started?
There are very few things that go wrong with a HOT and one is being taken apart and a few outside screws put too tight even by one full turn.
If it was given to someone else, the first thing I would do is look at the connecting screw that goes from the left lock to right lock. It should be flush on the right side (threaded side), if it is sticking out, back it off by one turn so it is flush.
Also if given to someone and they did not notice that the connecting screw is engraved, they could have mixed it up with the back trigger plate screw to top tang, the one that is behind the safety. They are almost the same length, but the head on this one is not engraved.
I hope this might help you if it was taken apart, if not, see Jerry.