A place for all kinds of smoked foods, smokers and techniques. Stick, pellet, briquette and everything in between are welcome.
Those dome thermometers are garbage in my experience.
Do you have a probe positioned right by the dome thermometer?
The probes are on the grates. You can see the one closest to the dome, on the top grate in the pics of my cook.
So then I wouldn't expect to read a temperature hewing close to that reported by the dome thermometer.
It's the latter. If you want to verify it then put a probe in the same spot as the dome thermometer.