Making smoke but not cooking?

Louisiana grill sl700

I've had it for about 5 years and it's performed very well! Today (50 deg ambient), I set the temp to 250 and it's running normally. It's feeding pellets (pit boss mix, dry, not new bag) and the burn box has fire. The issue is the display is showing 475+deg but it's definitely not that hot. I can rest my hand on the grill comfortably.. Using a separate battery thermometer the actual chamber temp in the middle is around 115 deg.

Is this typical of an RTD sensor going out of spec? I didn't catch any error codes but something is obviously wrong. It's medium on the scale of needing to be cleaned. I tried wiping off the probe but didn't help anything and only had a light coating on it.