R730xd inlet temp sensor not working

Hi,

We have 2 R730xd servers that were delivered at the same time.

One seems to be unable to display the inlet temperature.
The working one gives:

#ipmitool sdr type temp
Inlet Temp       | 04h | ok  |  7.1 | 21 degrees C
Exhaust Temp     | 01h | ok  |  7.1 | 41 degrees C
Temp             | 0Eh | ok  |  3.1 | 53 degrees C
Temp             | 0Fh | ok  |  3.2 | 50 degrees C

the second:

#ipmitool sdr type temp
Inlet Temp       | 04h | ns  |  7.1 | No Reading
Exhaust Temp     | 01h | ok  |  7.1 | 42 degrees C
Temp             | 0Eh | ok  |  3.1 | 50 degrees C
Temp             | 0Fh | ok  |  3.2 | 52 degrees C

and the idrac web interface says:

System Board Inlet Temp	Information Not Available

I have updated all the drivers etc. for the one that
isn't working but that didn't change anything.

Is there any known issues with these, or other
tips on getting the inlet temp displaying
some sensible values?

Thanks,
Neil