Noise on SAE 5000A when adjusting the sensitivity adjustment

Just  as the title says: I have an SAE 5000-A that I have owned for 5 yrs or so. 98%  I have no issues. However, I have bumped the slider a couple of times and it touched the extreme limits (read far-right) of the slider and this horrendous distortion/buzz can be heard. I played around and found it does the same thing when I move the slider to the extreme left. I have poked around various forums, looked at ChatGPT and even reached out to SAE (under their current incarnation) but the only answer I saw was ’this can be a problem because of the placing the slider at the extreme edges of motion’. Now, the wording of this didn’t say this was to be expected or... So I am wondering if anyone else has this unit or its ancestor, the 5000, and if you have observed a similar issue? I used deoxit on the slider/push buttons and that made the action a little smoother, but the extreme buzz/distortion remains.

Thanks a bunch,

Joe