We also have the same issue with a Kasli 2.0. Right after power on, the fan noise is high-pitched and unstable. After about a minute, it starts sounding like a fan should sound.
As of today the high-pitched noise is gone. I didn't check yet if the fan is still spinning properly.
What would be the expected behaviour (of the Kasli and other cards like Urukul, TTL, ...) if the Kasli is overheating?