I also mailed above to ZO and just got this answer;
"Sorry to hear your having problem after your upgrade, below are a few things to check/observe.
How is the head and single ECI GPS puck mounted, are they secure? They must stay secured to the boat and not move around during operation.
Are you seeing engine RPM at all times and during this issue or is it dropping out? It will follow the engine RPM but you should never loose it.
Also in the diagnostic menu do you have any faults, if so can you send a picture of that screen?"
The puck is secure, we will check the RPM question and diagnostic menu next time we are at the boat. If anyone has any input on above issue, please comment.