Found the solution.

During the update process, my server-settings.json file was removed, and needed to be re-created.

During the recreation process, I misconfigured the .json file.

The reason I didn't know this was happening was I have my server set to run as a service, under the local system ...

Just an FYI, I tried with a new, from scratch save file, and it does the same thing.

1. Starting a server as a service in headless mode. The server seemingly starts up but closes immediately.
2. Last lines of the server's log:

6.717 Info ServerMultiplayerManager.cpp:138: Quitting multiplayer connection.
6.717 Info ServerMultiplayerManager.cpp:776: updateTick(4294967295) changing ...

Not sure what is causing it, maybe it's my odd Windows Headless server setup, but I'm having an issue that when I attempt to connect to my server, it tells me the mod script for OIC is not identical.

I'm running the server as a service (under the system account) so it will start automatically when ...