I had a similar issue earlier this year. I think the problem is actually overfilling the DEF tank. I filled it but the pump (truck stop) was problematic and I thought it wasn't filling it all the way. It took my truck over 300 miles for the gauge to finally rise. Ironically, I was driving to the dealer to get the service department to diagnose the issue...
I fill my DEF at truck stations but after I had this issue I stop at the first click/shut off of the nozzle. Haven't had a repeat issue since then. I saw another post on a different forum with someone having the same experience.
I fill my DEF at truck stations but after I had this issue I stop at the first click/shut off of the nozzle. Haven't had a repeat issue since then. I saw another post on a different forum with someone having the same experience.