Error on applying forest undo

ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index System.ThrowHelper.ThrowArgumentOutOfRangeException (System.ExceptionArgument argument, System.ExceptionResource resource) (at <fb001e01371b4adca20013e0ac763896>:0) System.ThrowHelper.ThrowArgumentOutOfRangeException () (at <fb001e01371b4adca20013e0ac763896>:0) System.Collections.Generic.List`1[T].get_Item (System.Int32 index) (at <fb001e01371b4adca20013e0ac763896>:0) MapMagic.Brush.Undo.Undo.Perform () (at Assets/MapMagic/Brush/UndoBac.cs:241) MapMagic.Brush.Undo.Undo.OnUndoRedoPerformed () (at Assets/MapMagic/Brush/UndoBac.cs:185) UnityEditor.Undo.Internal_CallUndoRedoPerformed () (at <d1bec46880064709a5e713ad543e6d96>:0) UnityEditor.EditorApplication:Internal_CallGlobalEventHandler()