Nuendo Live Muting P.A

Hello
I was multitracking with Nuendo Live, MacBook Pro and a CL5. The process of multitracking was muting the P.A. I was using, not good. The only thing I may have been doing wrong that I can think of is using a non Apple dongle to have CAT5E from the laptop to the primary switch of the RIO racks. Has anyone one had a similar experience of their P.A. muting or have any ideas what I may have been doing wrong? Having the multitrack process muting the P.A. system is the worst possible scenario of course. Thank you.

Was the signal to the PA going through your DAW? If so, what was the status of the track(s) going to the PA?