I spent about an hour on the phone with comcast. Rebooted the gateway and actiontek's. Cable guy verified that no downloads etc occured at the time of the outage. Eventually I powered off all the MoCA boxes as they continued to allow wifi connections without internet access.
The condition evedentually cleared itself. The last thing I did was disable and reenable MoCA at the gateway (I had done this several times). When I repowered the garage MoCA, it showed up as a connected device. Now all 3 actiontek's are operational. <Edited>