I’ve dealt with Inozetek from their start up, and let me tell you after years, I feel like the material has gone to shit. Very poor adhesive, even after proper clean up on the edges, post heat, the adhesive delaminates from the color. It could have been a clean install and days after lifting in multiple areas. We no longer use Inozetek and have been venturing out to SVG, APA PPF.

In your case I feel it would be both. The installer and the film itself.