I have the Nonrev for around a month now. I got it out of the case and I saw this. When I looked at an earlier pic it was already visible a bit.
To be clear: The bass lives in it's case in a room with a normal, steady temperature. The case lies flat, and there was nothing on it. It's not near a heating device. The bas is strung with factory strings in the normal EADG tuning, and I never tuned it in another way.
Gibson offered me to take it back and I'll get my money back, which I will accept. A pity. It was a demo model I bought at the artist sale, so cheaper than normal, and I won't buy a complete new one.