crashes during siege defence

[gammadion97]

Exception information
Type: System.IndexOutOfRangeException
Message: Index was outside the bounds of the array.
Source: TaleWorlds.Library
CallStack:
at void TaleWorlds.Library.MBList2D.set_Item(int index1, int index2, T value)
at void TaleWorlds.MountAndBlade.LineFormation.RelocateUnit(IFormationUnit unit, int fileIndex, int rankIndex)
at void TaleWorlds.MountAndBlade.LineFormation.AlignLastRank(LineFormation formation)
at void TaleWorlds.MountAndBlade.LineFormation.FillInTheGapsOfMiddleRanks(LineFormation formation, List relocatedUnits)
at void TaleWorlds.MountAndBlade.LineFormation.RemoveUnit(IFormationUnit unit, bool fillInTheGap, bool isRemovingFromAnUnavailablePosition)
at void TaleWorlds.MountAndBlade.Formation.RemoveUnit(Agent unit)
at void TaleWorlds.MountAndBlade.Agent.set_Formation(Formation value)
at void TaleWorlds.MountAndBlade.Agent.OnRemove()
at void TaleWorlds.MountAndBlade.Mission.EndMissionInternal()
at void TaleWorlds.MountAndBlade.Mission.CheckMissionEnd(float currentTime)
at void TaleWorlds.MountAndBlade.Mission.OnTick(float dt, float realDt, bool updateCamera, bool doAsyncAITick)
at void TaleWorlds.MountAndBlade.MissionState.TickMission(float realDt)
at void TaleWorlds.MountAndBlade.MissionState.OnTick(float realDt)
at void TaleWorlds.Core.GameStateManager.OnTick(float dt)
at void TaleWorlds.Core.Game.OnTick(float dt)
at void TaleWorlds.Core.GameManagerBase.OnTick(float dt)
at void TaleWorlds.MountAndBlade.Module.OnApplicationTick_Patch2(Module this, float dt)