It sounds like NUT is still picking up stale Netclient config and immediately acting on it, which triggers the shutdown. I'd suggest fully clearing any remaining NUT config (including `/usr/local/etc/nut/*`), rebooting, then configuring Standalone from scratch with the USB UPS only connected. Also double-check that upsmon is set to **master** and that no old UPS definitions pointing to the NAS remain. I reported same at football bros.io
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