I had that happen 1 time last year; it appears that the truck forgot to add the power of one of the motors to the gauge. I drove it home just fine, restarted it and haven’t seen it since.
I had a similar issue early on in my ownership where the truck was limited on power with a near full charge. I was on a short road trip of about 110miles, but got the best mi/kWh of any highway drive. Might be something Ford should add as a feature, similar to Rivian.