John, it may have been due to how deep the probe was in the meat, and what kind of temp probe you were using. Initially, the exposed stainless of the probe will heat, and transmit that higher temp into the end of the probe, thus causing a false temp spike. Once the temp stabilizes, it seems to get more accurate. I've experienced this when trying to probe smaller cuts of meat, where a lot of the probe is exposed. Only explanation I can come up with, that makes sense to me.