Comparing the Two Types of Mutāwaʿah

Characteristics of Form VII (Infiʿāl): Intransitivity, Manifestation, Resulting Action, Equivalence, Root Restrictions and Independent Use

The textbook separates these because the initial actions are different:

Book topicInitiating formExact source pair
Third characteristicForm I (faʿala)كَسَرْتُهُ فَانْكَسَرَ
Fourth characteristicForm IV (afʿala)أَغْلَقْتُ الْبَابَ فَانْغَلَقَ

Both second verbs describe results. The distinction lies in whether the first verb is Form I or Form IV.