After first verifying that no critical measurements were being taken, I performed an nmap port scan of the H1FE VLAN. This caused the daqd process on h1broadcaster to fail, it was subsequently restarted by monit.
I ran the port scan a second time, and h1broadcast0 daqd did not fail this time.
The log files show a correlation between port scan and the failure. I will exclude all DAQ hosts from future port scans.
log file for this event attached.