Some linear travel up to a pronounced tactile point. Given that you have to exert a lot of force to get over that point, you will almost certainly bottom out.
I think what happened here is that you are used to the linear switches in your Deck, and the Black Alps with the tactile point up near the top of the travel, and thus found the buckling spring to be quite different. I misread your description as a description of a problem I had with a Model M I was fixing so I jumped to conclusions. Long story short - everything is ok
The odds are that if there was actually a problem with the Model M, it would be hideous to type on.
Nut and bolt mod is needed when a large number of plastic rivets have broken off.