+1, having the same issue as OP
As mentioned above about friction brakes being applied, I noticed it after enabling the feature to apply friction brakes when limited regen is available. I happened to be at 76% charge when the noise occurred. And I have one pedal driving enabled (stopping mode =hold).
Try toggling on/off the feature (apply friction brakes when limited regen is available) and see if the problem (noise) goes away.
Makes sense now that a noise (brake pedal/assembly) would occur if friction brakes are being applied automatically by the system when lifting off the accelerator pedal.
But I would think the ECU could bypass the brake pedal to activate the friction brakes, but it sounds like it's using the brake pedal or the assembly behind it to activate. Manual states pedal may be engaged during this event, but pedal function is still operable (can use brakes manually) if needed.