Dynon EMS 120 crazy RPM.

Sometimes normal. Other tines red warning at a normal reading ie 2300 red comes on. Then RPM jumping around sometimes red sometimes way high. The engine is running smooth and eventually the RPM will settle down and read normal.
Not sure where to start. Dual P mags. 0 -360

Electrical connectors??

I would investigate the electrical continuity from the source of the signal to the EMS and your grounds???