wyred4sound Sonos Port - garbled noise

Hi Everybody - anyone having issues with their w4s modded Sonos Port?  Mine has started garbling/distortion at anything but the lowest volumes.  I'm guessing a recent sonos software update may have triggered it.

I've had it for a few years now, so no complaints - but wondering if anyone else is noticing the same thing, or its just my unit.

Dave