Hi Chris,
Yes. There is issue in 15.1R5 Junos version for temperature failing in EX2200 device.
Please find PR details which is fixed in 15.1R6 Junos version.
PR 1255421 - Temperature sensor failing / EX2200 Version 15.1R5
however there are Memory Leak issues in 15.1R5/R6 for legacy EX devices. Hence it is better to wait for the fix.