Problems like these are fairly unusual, so I have to speculate a little in what could be wrong, but: Most likely cause is probably a cold/cracked/bad solder joint on one of the i2c pins. These are called SDA/SDL on the tensysaber pinout, or pin 18/19 on the teensy 3.2 pinout. There are a lot of other potential reasons. The solder joints under the motion chip can crack, the i2c pullup resistors can be damaged or pop off, there could be a short somewhere (Again, on the i2c pins)