SG5100 shutting down unexpectedly

[pfguy2018]

SG5100, running 23.09.1 (although same behavior was observed on 23.09 as well)
Several times, in the middle of the night, the unit shuts down unexpectedly.
The relevant section of the system log always displays something like this:

Any suggestions for how to fix this?

[SteveITS]

@pfguy2018 Possibly https://forum.netgate.com/topic/184928/system-shuts-down-when-ups-does-a-self-test if it's using NUT.

[pfguy2018]

@SteveITS Thanks! Have taken my question to that thread.