The issues was a missing depsgraph tag after adding the hook modifier. Because of this, the depsgraph did not make a new copy of the object, which led to a discrepancy between the number of modifiers on the original and evaluated object.
The issues was a missing depsgraph tag after adding the hook modifier. Because of this, the depsgraph did not make a new copy of the object, which led to a discrepancy between the number of modifiers on the original and evaluated object.