Another little different quirky thing. Have you upgraded to the latest version? If not, then upgrade, if you have then check that all of your connections are ok, small amounts of electrical instability/static can affect the OS. Move all your sliders quickly up and down , blow out any dust that may have collected in and outputs.
If all fails and you have upgraded, re run the Last OS installation, only as a last resort, make sure you back up your registrations, so you can reload your custom sets after the re install, And good luck, we mostly love the Audya, but it does seem to do some strange things occasionally