all drawing tools stop working

Hello. Thank you for the app. But I got the following problem: after I made several copies of the “ShapesManager” prefabs.
For some reason, all drawing tools stop working. Although the asset did not change anything.

Writes the following in the console:

MissingReferenceException: The object of type ‘DrawingContents’ has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.

IndieStudio.DrawingAndColoring.Logic.GameManager.LineFeatureOnClickBegan () (at Assets/DrawingAndColoring Extra/Scripts/Game/GameManager.cs:298)
IndieStudio.DrawingAndColoring.Logic.GameManager.UseLineFeature () (at Assets/DrawingAndColoring Extra/Scripts/Game/GameManager.cs:272)
IndieStudio.DrawingAndColoring.Logic.GameManager.Update () (at Assets/DrawingAndColoring Extra/Scripts/Game/GameManager.cs:185)

Thank you