Hmmm. I have polarized lenses and never had that issue.
It's dependent on a few factors (glasses and viewing angle being a couple). I admit my sunglasses are cheap lol, but if you look online, the rainbow effect is a fairly common complaint with tints. I also have to say that it's fairly faint, so it's not like I see double rainbows blocking my view.
When I got my windows tinted, the shop owner gave me a 4x4" sample of the Crystalline 70 before I made my decision, and the first thing he mentioned was "if those sunglasses are polarized, you'll probably see weird colors at times." The rainbow effect definitely showed up with different levels of severity depending on how I held that cut-out.
*And so I have a more useful contribution to this thread....*
The tint shop I went to had a small bright bulb rigged with swatches of tints below it. I believe it had the 3M Color Stable 35, Llumar Air 80, Crystalline 70, and plain glass. If you put your hand under the bulb with just plain glass, it burns. Crystalline 70 allowed the least heat to pass through while maintaining a light shade of tint. To this day, I'm still happy with my decision.
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