So I swapped my wheels from my gravel bike, which runs the same wheel set with the 105 level rotors and at first had no noise, but started noticing it on a big descent when braking at over 30 mph. Then I'd notice it when braking at speed for the rest of the ride, but less so than with the Ultegra Ice Tech's. Again, I was confident in the braking power despite the noise.
[MENTION=332446]dsaul[/MENTION] - I think you may be on to something. I'll check that out.