Chosen Solution
It still registers but it doesn’t have the same sort of springy feeling. Its worth noting I think started after a fall on the trigger. I’m guessing some piece of trigger assembly either broke or got out of alignment. Unfortunately I can only seem to find on trigger repair guides for the 3DS and those seem to be about replacing a flex cable not a mechanical issue (presumably they wore out the actual electrical switch component).
Usually after a fall the plastic around the button gets bent into the button a little bit or sometimes the button part that is inside the console rubs on the plastic. What I do is inspect it very carefully around where the button is and find where it is sticking. They I either try to bend it back or I remove a small amount of plastic with a hobby knife or razor blade until it moves freely again. This fixes the vast majority of these types of problems. I hope this helps.
