Audio Sharing - FIOS HD Box, LU642 Matrix, Russound

[Topfox]

All,

Currently been working an issue with my dealer. I have a russound audio system in my house. In my basement I installed basically a sports bar setup. 5 - 4k tvs, 1 - Samsung Soundbar, C4 and Leaf 4k Matrix LU642. So i basically have a center tv that the sound bar plays sound from, all the other tvs are muted. For times when I want extra sound, I had the russound speakers wired to the system through the matrix switch. When we originally did the setup everything worked great. I could select the russound zone, and select any of my 4 FIOS cable boxes and the sound would play over russound in addition to the sound bar. 

While troubleshooting 4k and HDR recognition issues we updated drivers and firmware with the matrix switch. This then made the cable boxes stop functioning with the russound. You would select cable box there would be a brief static noise, then no sound. My dealer came over and added a coax audio connect from each cable box to the matrix switch, and I can now hear the cable boxes over the Russound again. However, when I turn on the russound zone and add a cable box I still get the static and no sound from the first cable box I select after turning on the zone. If I switch between cable boxes the sound will play, and no static noise to start, even the initial box will play sound and everything will be fine. If I turn off the russound zone, then I have the same issue again until i switch to a second cable box. 

Anyone have any ideas?  Fios boxes are set to Fixed audio, and Stereo output. 

Again Previously it all worked over HDMI until we started updating firmware to try and get 4k to pass. 

I should note if I play sound through xbox or airplay I dont have this issue the xbox is only hooked up with hdmi to the matrix  so it is specific to the fios cable boxes only.   

Thanks