Yes, prior to 15.1R5 it worked fine. I was on version 15.1R4
I observed the issue on two EX2200 and wouldn't expect an identical hardware failure at the same time.
Just rolled back to 15.1R4 and temp sonsor is ok:
root@switch> show chassis environment
Class Item Status Measurement
Power FPC 0 Power Supply 0 OK
Temp FPC 0 GEPHY1 OK 25 degrees C / 77 degrees F
FPC 0 GEPHY2 OK 30 degrees C / 86 degrees F
FPC 0 GEPHY3 OK 35 degrees C / 95 degrees F
FPC 0 GEPHY4 OK 45 degrees C / 113 degrees F
{master:0}