Yamaha A-S2000 - question for owners

I bought a 2-yr-old Yamaha A-S2000 and have a concern about the tone controls. The knobs snap into place at 12 o'clock like you would expect, but when I turn them to adjust bass or treble, sound cuts out briefly. The same thing happens when I turn them back to 12 o'clock.

Has anyone else experienced this with their own A-S2000? Would you mind checking to see if yours does the same thing please?

Thanks!