Default [Q] Google voice search kicks offline after docking

Hi everyone,

This is my first time posting on the site so be gentle

I've noticed while plugging my SGH i747M Galaxy s3 into my car dock that the Google Voice Search comes offline and the solid mic symbol is replaced with a hollow one. In other words, no more 'Ok Google'. When I touch the mic I get an acquiring message but it fails after a 5sec attempt. If I unplug the phone from the dock, it remains hollow and I usually have to reboot. I'm running Quantum V3 kitkat and my modem and bootloaders are current.

What also gets me is that if I plug my wife's Nexus into the charger, I get the same result. She's on stock 4.2.1 unrooted. This tells me it's a Google thing, not phone specific.

Any ideas?