My 2024 Duramax 3.0L DEF dash fuel gauge seems stuck on full, with about 15k on truck still under warranty. I noticed it had not moved after about 2.5k miles since last refill, where it’s normally down 1/4 - 1/3. I try to refill when it’s down to a quarter full on the dash gauge with fresh DEF. It’s well above freezing, and using approved DEF, cap on tight. Any ideas? Thanks