I used pretty much the same way of checking if an actor is on screen in my project (ue4.26). However, I noticed one strange thing (or maybe I just don’t understand this fully). When I’m turned 180° from the actor (or wherever in the range of some -+60° from that point), the values returned stop changing, and it may give a false impression that the projected actor is actually on screen. So I started printing the boolean being returned: it was true when actor is on screen, and offscreen, but false only in that range where values returned stop changing (when the actor is offscreen, behind us). So, I added another pin to my AND operation and plugged the boolean returned from ProjectWorldToScreen. It produced the desired result and check seems to work every time.
Does anyone know why this happens though? I can’t really wrap my head around it, but I guess it’s hard (impossible) to project something to screen if it’s basically on the same parallel 2d plane or something like that…