Ok a few things on this one:
Check includes/discovery/functions.inc.php. I've updated this as it looks fundamentally wrong as is. This PR was passing those values across and they were being NULL'd out due to this.
I've updated poll_sensor in includes/polling/functions.inc.php to support custom temperature includes and made use of it for this PR. This really shouldn't effect any existing temp sensors.
Excuse the dip, this is when I was coding the PR.
Added Temperature sensor support for NetApp