Don't use foil tape on the probe it can have negative effects. (not account for the tape as much as the room) You might try a couple of things. First check all the flexwatt connections make sure they are all perfect. The second is to place a strip of foil tape down on the flexwatt where the probe will be. Then place the probe on top of it and use eletrical tape to secure it. This should help even the heat where the probe is rather than isolate it.