I did some testing with a 2060 KO today, and using PX1 I was able to figure out what's happening. What you hear is the click of the fans turning off and back on, which is normal for these style fans. It seems that any fan speed below 40% can potentially trigger than fans to randomly pulse down to 0 RPM then back up to speed. As long as the fan speed can be manually reset to 40%, the fans will not turn off and on. The lower you set the fans below 40%, the more likely it will start to happen. I tested down as far as 29% fan speed, and one time out of 12 tries the fans operated normally at 29%. Likewise I was only able to trigger the off/on pulsing once at 36% and not at all at 37% or higher. I could fairly reliably set the fan speed down to 32-33% by lowering the curve by 1-2% at a time without the fans pulsing. At 31%, it occurred nearly every time and I would have to start over.
Note I was not able to reproduce the issue without using PX1 running, but that may potentially vary from card to card.
For now, using PX1 to manually set a fan curve no lower than 40% will prevent the fans from shutting off and back on, and causing the click. You can try lowering the fan speed percent one or two percent at a time to get it lower without the pulsing off and on, but if it happens again just set the fan speed to 40% and try again. I don't recommend trying for less than 32% unless you are very patient.
I'm having our engineers look into it further and see if we can do anything about the fans pulsing off and on.