I got an excellent piece of advice from one of the TNR groups I belong to. I have a community where many of the cats have watched me trapping enough to know what happens when that trap springs. If you have that same problem, try feeding only using the traps for a couple of days, but keep the trap door open with a zip tie or other method. That way, the cats will get used to being fed this way. Then set the trap and hopefully get them.