Replacement screen protector perforated cutout issue

I bought the Raz+ screen protector replacement kit. All went well until I had to remove the plastic guide. The screen protector is cut with rounded corners. It is a rectangle with a perforated cutout for the rounded corners. Except on my the perforated cut wasn't a clean cut and when I tried to pull the excess off, it tore the screen protector and I had to toss it in the trash. Are all like this? How do you get the perforation to separate and install it cleanly??? I ordered a second protector.