Never had/ heard of any issues with them on my end but I would not bet against that. Nevertheless chances of that happening are quite high on tires that have such a great amount of material vs traditional tires. It's very difficult to combine a rigid thread with a flexible casing and expect the innate rigidity of the thread to comply.

The probability of that happening is definitely more in the rider's favor with everwears than thickslicks though. They've been produced for significantly longer than thickslicks have and sourced from Panaracer by Soma who make excellent tires. Panaracer is owned by Panasonic and make tires that meet and exceed NJS certification.

You will get cracking on everwear tires though over time. This is a result of UV exposure from the sun brittling the outer layer of side-wall rubber as with any sort of tire exposed to the outdoors. This should not be confused as separation in the sense that I am implying about thickslicks.

Thickslick separation is more of a clean "peeling" along manufacturing seams.