Disks stopped reporting temperature

[Zeff]

After 24 hours of uptime, all five drives have stopped reporting - 3 HGST and 2 Seagate.
FreeNAS-11.3-U1

Using this:

midclt call stats.get_data '[{"source": "disktemp-ada3", "type": "temperature", "dataset": "value"}]'

I get this:

{"about": "Data for disktemp-ada3/temperature", "meta": {"start": 1584130500, "end": 1584134100, "step": 300, "legend": ["disktemp-ada3/temperature"]}, "data": [[null], [null], [null], [null], [null], [null], [null], [null], [null], [null], [null], [null], [null]]}