Yeah the fuel gauge does that, it’s how a lot of modern gauges work, when you switch the engine off, the needle will just stop wherever it sees fit. I the ignition needs to be on to get a correct reading.
I can’t remember if yours is an F or TF……. The F ride pretty good if they’ve not leaked all the nitrogen gas outta the suspension spheres and someone has tried to compensate by pumping in to much hydragas fluid in to get the ride height correct.
If it’s a TF then they don’t ride as well a an F with it’s suspension in good condition, but they are more consistent as they age.
"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"