On my MX Anywhere 3S, the button (middle button) just below the scroll/wheel keeps reverting back to a "mode switch" button, no matter what I map it as (e.g. middle mouse button, spotlight, etc.).

When i press this Middle Button, generally it will do the task I've re-mapped it to do, but every day, at random, it reverts back to it's default "switch mode" and changes my scroll function from ratchet to smooth.

this is very frustrating and needs to be resolved.