I have been waiting for more than half an hour now, I did a server restart as well + some slomo 100. No thralls are getting deleted. Not sure when the function broke because I know it worked at one point but it is not working now.
Genuine question as I only play on official servers and I am not overly familiar with server settings.
How does MinionOverpopulationAllowed work? What would setting it to zero do to your scenario?
Hmm, good question and well spotted. Not sure if this setting was there before. It is not in the UI. This might explain why it is not working. It might be newly added to allow for the rescued thralls. I will set it to 0 to test.
Changing the setting for allowed population to 0 did the trick. The setting is only available via the ServerSettings.ini with the default value being 10. Thanks @Exiled1
MinionOverpopulationAllowed=0
The thrall deleted was random. Out of the 3 placed thralls, it was the horse that got deleted. It was the 2nd oldest thrall.