I have not heard of your problem before so I am guessing here. I have had as many as 6 DW's from the Monson era in my collection so I have a bit of experience.
What I would do next is look at the geometry of the problem very carefully. the latch is held in to the frame so it is not supposed to be able to be forced out of alignment when you push it.
So, with an empty gun, actually thinking about it, I would even pull the barrel off since it is just more in the way, look carefully at the latch while you force it open. How does it move?
Mine is caught pretty tight and I just don't see how it would force out easily.
Once you see how it is forced out, then determine if the frame or the latch is the problem. Look carefully at both and puzzle out the geometry. If it is the latch alone, then you could just buy a new one from DW and have a local smith or yourself fit it. If it is the frame, then send it back to DW.
They are good folks and DW makes good guns. My personal favorite is my 722:
Here is 50 shots at 15 yards offhand from it. Great gun and built like a tank!
Let us know what you find. I will check in tomorrow after work.