My Cinder was wonderful, but would not work with any case I tried. (Apple Silicone, Spigen Rugged armor capsule). Thinking it was out of alignment, I removed the Cinder and tried to wash it and reapply it. That REALLY did not work. Hence my purchase of the Ice Max.
I just applied my Ice Max 3D to my 6s+. Cutouts seem OK. As you describe, I noticed the clicks as I press down on the ends of the protector. This may be a dust collector around the openings. It did take some work to get rid of the bubbles. I used a small plastic box corner to get rid of them. Massaging out the bubbles was not going to do it. The Ice Max adhesive is indeed different from the Cinder. I will wait to add my case until I think the adhesivee is set.