Red X through RPM or other

To add, condition goes away with an engine restart.

When this happens, is there a lane warning light on (or flashing)?

Yes, Lane A flashes during issue. (Original post edited to add this) thx

If the lane A light is on or flashing, then the problem is with the Rotax side, not the EFIS side. This is similar to the gauge dropout that you would see when you turn off Lane A during a preflight check.  The problem is that you have a lane fault, the red X on the EFIS Engine display is a symptom of the lane being in fault.  Do you have access to a BUDS dongle so you can download the fault log? 

Both RPM and coolant temperature are processed by Lane A, so this could be a problem with one of those sensors, but it may not be. Lane A could be going into fault for another reason and dropping out the gauges. One thing to try is simply cycling Lane A with the engine running (instead of a complete shutdown).  If that clears it, this could be a problem during starting the engine that puts Lane A in fault.  Possibly even a low voltage condition while the engine is cranking. Again, you need access to a BUDS dongle to see what is going on.  

Thank you, I will try and find a local mechanic with the buds software. I am in Wilmington North Carolina if you know of anybody