I wouldn't trust a dome therm anyways, because it's not going to give an accurate reading of what the actual temp right below grate level is.
Not to mention, depending on how much cold meat is next to the therm, it's gonna read even lower. Nope, wouldn't even pay attention to it.
If I owned one, I'd probably perform a thermometer delete mod, and cover the hole with a small sheet of aluminum flashing or something.
Example of a simple therm delete mod:
The lower thermometer that I installed has a 6" stem, so it sits right under the center of cooking grate. That I will trust :)
After about 2 cooks, the sheet aluminum is completely sealed up with bbq goodness.