The problem with the touchpad on the PS4 is that it's prone to accidentally being tapped during moments of intense combat, thus resulting in a mouse click, which ends up deselecting or changing targets unintentionally and sporadically. It's also enabled by default and players may not know how to disable it, or that it's causing targeting issues.

The solution is to make so double tapping the touchpad performs a single click. Right now a single tap resulting in a short delay then click. This is just a very poor design, and I do not understand why you didn't fix this problem when you added touchpad support to the game.