The capacitive probe runs down the tank right by the fuel filler.
So when you are filling the tank it is possible to 'wet' the probe and get an incorrect high/full fuel indication.
It normally goes away after a few minutes as the probe drains/dries.
It can also read high from fuel sloshing from taxiing over rough ground.
It is possible this depends on the fuel and oil used- I am using non-laced 95 with Castrol TTS (aka Power1 2T) at 50:1.
Moral of the story is to never trust a fuel level indication without verifying by sighting the tank level through the seat back inspection holes, and a good idea to mark the tank levels there in tail-down attitude.