Clicking noise from rear disc or cassette on SRAM Red

Does anybody have any idea what this clicking noise is, or where it's coming from? Brand new Tarmac SL8 with SRAM Red.

I've tried everything. It happens after heavy or long braking periods. It feels like temperature changes causes it. It starts clicking mid ride or when I stop the bike, with the bike still.

Thing is I went to a shop and they said it was the disc. The lent me a test Shimano RT-MT800, I went out for a 140km ride with it and I didn't hear any noises. But then again I went to my LBS to get the SRAM Red rotor replaced, they lent me a test SRAM Centerline disc and… It clicks as well. I'm confused, before all that I tried a DT Swiss wheel instead of the stock Roval, just to make sure it was not the wheel itself or spokes I installed the SRAM disc and the SRAM cassette on it and I was still getting noises.