R2 button triggers by itself?

I use the normal Nacon ps4 controller. Recently it has sometimes been the case that I shoot in fortnite and then he continues to shoot briefly or starts right in the middle. But it is also the same with other games. What can I do?

You have a hardware defect.

You could unscrew (with a clue), look, look for the cause and fix it.

Alternatively, you can buy a new controller.

It may be worthwhile: first look, then buy again