CRSS12 deck pitch fluctuations & Stop button not Accurate

I have two CRSS12s and an S11 mixer.

Problem 1 - On the left deck, the pitch display fluctuates up and down, while the right deck remains stable.
Problem 2 - on the left deck, there is about a one-second delay when pressing the Stop button before playback stops. The right deck responds immediately.

I've checked that all firmware is up to date, and I'm running a Mac mini M4 Pro with 48 GB of RAM. I've also checked for Mag-Clamp misalignment, timecode drift in DVS mode, and whether the spindle is dirty. Everything appears to be in order.

Does anyone have any suggestions on what else I should check in the software Rekordbox or on the hardware. Thanks