[adavisxpn]

Update:

I tried using both a managed and unmanaged switch and no luck. It seems like now matter how I connect the S3 to the Mac Pro as soon as EUControl connects to the S3 it kills the other ethernet connections.

The work around for now is to use Thunderbolt -> Ethernet adapters for the other networks (everything but the S3). By disabling the connection, unplugging the adapter, plugging the adapter back in and then re-enabling the connection I can get the connections to come back.

Kind of a drag but I do get the the S3 is not supported on 10.10 at this time. Hopefully Avid gets an update out soon.