BBQ Guru- is this normal?

used my DigiQDX for the first time today on some ribs for work. I clipped the pit probe from the Guru to the temp probe of the egg. I was also using an ET-73 just for monitoring the new toy. I set the Guru for 250. After a few minutes, I noticed that the guru was showing 250, but the egg and ET-73 were reading about 315! I know that these things can be calibrated but don't they do that before it ships? I know that grid temp and dome temp are different, so just out of curiosity, I put the guru probe on the cooking grid. The temp showed around 225 or so, and the guru's fan kicked on. Once the guru was at 250, the egg temp was approaching 360 or so. What am I doing wrong? I made sure that the probe from the guru wasn't touching any food- I'm stumped.