I thought I read somewhere that the Zagg protector for the S7 wasn't even out yet? This is the first I've heard of issues with Zagg. I used 3 different glass screen protectors from Verizon for my S6 and each one had the halo.
You're correct. Zagg will have a curved glass screen protector for the S7/Edge, it's just not available yet. You can sign up to have them email you when it becomes available.