Net3 2 port node dropped network connection

System has been stable for several months with a variety of shows.  Ion Classic Win 7 with 4 port Net3 in rack and 4 portable 2 port nodes in use.  All nodes are static IP addresses and RDM turned off in shell and configuration in each node.  Board started up for show tonight and movers and chase lights on shoe box dimmers were misbehaving.  (Ironic as the show is Ain't Misbehavin')  Had some control but finally homed them and they went to their "lost DMX" position and not home value.  Node was on catwalk so i was able to reach it and saw that output was flashing.  Unplugged from ethernet port, replugged and successfully outputted DMX after reboot.  

Can't imagine that it would have any impact on problem but board is set to wait for network before starting.

Any thoughts on why only one of our nodes would need to be rebooted?