Update: Fagor Automation Toronto comes through again!
Investigate following error on all 3 axis
Solution: Parameter#29 Servoff=0001 (Servo offset)
Run each axis in jog mode (10%) and verify following error </= .0001"
The cause for the shift is unknown, but likely reason is electrical noise. Had the Electrician verify that all ground connections are OK. I'm still concerned that something shifted, but the shift effected all 3 axis equally, which indicates a systemic shift. many thanks to Mohit at Fagor Automation Canada.
If you have a Fagor, and need expert advise ask for Mohit.