Crash while raiding a desert map

My game crashes to desktop while raiding a desert map, I build 2 catapults and start bombarding the enemy settlement but as soo as I give a move order to my nobles the game crashes with the following error code  

```
Noble Fates Critical Error:
NullReferenceException: Object reference not set to an instance of an object

Report: 24ffb45e-e176-4098-836c-29589887428c

DefendScheme.ScorePoint (System.Boolean initial, System.Boolean preferInPrioritized, System.Boolean preferProtectPrioritized, Character character, GuardPosition position, Actor target, CharacterRangedAttackType rangedAttack, ProjectileType rangedProjectileType, System.Collections.Generic.Dictionary`2[TKey,TValue] pointDetails) (at <8b146f2174c243bda9849f65469fd700>:0)
DefendScheme.EvaluatePositions (Character character, System.Boolean initial) (at <8b146f2174c243bda9849f65469fd700>:0)
DefendScheme.Tick (System.Single dt) (at <8b146f2174c243bda9849f65469fd700>:0)
SchemeManager.Tick (System.Single dt) (at <8b146f2174c243bda9849f65469fd700>:0)
ManagerBehavior.Update () (at <8b146f2174c243bda9849f65469fd700>:0)
```