Have you checked the temp calibration with an external thermometer in the water bath? My BT model is about 2 degrees off and it runs hot (ie: 129 on my display actually puts the water at 131).
Also, could you have seared it too long? I’ve found that with thin cuts of meat like 1 inch thick, even up to almost 2 inches, in order to get a good sear without leaving it on there and cooking the meat I have to get a cast iron pan super hot. Like pan is smouldering and the smoke alarm goes off kind of hot. Or I’ll sear it on my gas grill that I modified to get up to around 850 chamber temps on full. These kind of temps give me sear times that are only seconds per side.