Could be...I was relying on the probes before I got my Thermapen. Two days ago I smoked a tri tip with probe b. The temp from the probe stayed close to what the thermapen would read till the end....about the time I was going to start a reverse sear, probe had been at 117 for a while....now the pen read over 136 ??? Would have been well done if I didn't have the 'pen
Time to check your probes in hot and cold water. You can check it against your Thermapen if you don't want to go to the trouble of boiling water and making a ice bath.
Just an observation, I washed my probes for either the RT or the Thermaworks Smoke and got the connector wet. It was way off until the moisture "cooked out" of it. If you did wash them, maybe heating the oven to 200F and leaving them in there for a couple hours will dry them out.