Error Message causing fps drop down to 1

[PotatoeTater]

System.NullReferenceException: Object reference not set to an instance of an object
  at RimWorld.PredatorThreat.get_Expired () [0x00000] in <filename unknown>:0
  at RimWorld.Faction.FactionTick () [0x00000] in <filename unknown>:0
  at RimWorld.FactionManager.FactionManagerTick () [0x00000] in <filename unknown>:0
  at RimWorld.Planet.World.WorldTick () [0x00000] in <filename unknown>:0
  at Verse.TickManager.DoSingleTick () [0x00000] in <filename unknown>:0
Verse.Log:Error(String)
Verse.TickManager:DoSingleTick()
Verse.TickManager:TickManagerUpdate()
Verse.Game:UpdatePlay()
Verse.Root_Play:Update()


Error message will continue to generate infinitely.

[Calahan]

Please can you post your log file (as an attachment). Details on where to find it can be found in the following thread: https://ludeon.com/forums/index.php?topic=513.0

[ison]

I'm not sure what exactly caused this, but in A18 it won't cause error spam. Thanks for reporting.