They get weird if they start to go bad, too. Just last week I was setting up for a smoke, got my Maverick 732 running, and the meat sensor was reading 20° cooler than the grate sensor at ambient (it was about 80° outside). I placed them both inside the smoker, just on the grate, and as the temperature got to 250° they read exactly the same. Pulled them out of the smoker, let them cool down, and they were 20° off again.
Turned off the Maverick, turned it back on 10 minutes later and they both read the same temperature at ambient. Ordered a new meat sensor, and all is right in the world again.
Not sure that story helps you, but just thought I would throw it out there.