What is the formal difference between ḍāʿafa and ḍaʿʿafa?

Seven Semantic Properties of Form III (Mufāʿalah): Participation, Equivalence, Causing a State, and Independent Uses

• Both start with augmented hamzah.
• Only the final radical differs.
• Both are basic triliterals.
• The former adds alif; the latter doubles the middle consonant.