Out on my quad today (2023 1000 Overland) and there was a noise coming from the transmission/drivetrain - loud enough that I returned home.
It was like a rattling or grinding noise - never heard it before today.

It only happens when I release the throttle and the engine braking comes on, and also when the engine braking cuts out due to reduced speed and I'm freewheeling.

When i'm pulling away it's fine - loads of power, usual engine sound, no strange noise.
I'm concerned enough that I don't want to ride it to the dealer in case I damage something.

Anyone else heard anything like this?

Give your clutches a good look over
One way may be gone

Also Only because I just had a similar situation an sounds
Also check the rear differential
Mine had the pinion bolt broke in it an it had the same sounds diff was full of metal