Sorry to hear about this issue.
If you haven’t already, could you first try connecting to the Device Manager with the Rose in update mode and reinstalling the latest firmware version to see if that resolves the issue?
If it doesn’t, can you try connecting to the Device Manger with the Rose booted normally, and then let me know what happens when you adjust Mix or Rate using the software? Does adjusting Mix using the software still control the Rate? Or does it work correctly using the software?