Roon, Expert Pro, and a major issue with RAAT

[mdconnelly]

This one has me stumped... I recently took my system apart to cleanup, dust-out and do a bit of rearranging.  When I got it back together, all seemed well.  Roon was able to stream via Roon AIR without a problem.    But when I switched to RAAT (which previously had been working fine on a 10/100mpbs link), things went bad... extremely loud, distorted music.  After immediately stopping playback, I switched back to AIR and it played fine.  In looking closer, I noted that the Roon RAAT zone was no longer showing the ability to control volume whereas AIR was showing the volume control correctly.  Clicking on the speaker icon, Roon was showing fixed volume.  That wasn't right but might explain why the music got so loud (but not why it was highly distorted). 

     

So I went into Device Setup for my RAAT zone which showed that Volume Control was correctly set for Device Volume.  But clicking on Volume Limits showed everything zeroed out, including Device Limits.  Something was clearly wrong.

   

I was stumped but on a whim, I decided to swap the ethernet cable to my Expert Pro.  Once I did, everything went back to normal!  I then put the old cable back and sure enough the same problem reappeared.  WTF?   How can a bad cable allow AIR to work but not Roon RAAT?  Worse, why did Roon still see the Expert Pro yet not pick up the correct Volume Limits?

Has anyone seen anything like this?  I have posted a question on the Roon Support forum but without a reply as of yet.