It's a server uptime issue. After the last update, the daily automatic server restart was disabled to find out how long to server would actually run for before crashing.
If the server runs for too long (more accurately if many people do too much stuff) then rumors and base side NPC stuff stops working. As the server wasn't automatically rebooted after 24 hours, this problem became noticeable. I'm not sure if this is actually a mod problem or a generic FL server problem.
The server has been restarted and the rumors and other base NPC stuff is now working.
Proud member of "the most paranoid group of people in the community"