The n is not changed to ṇ when a pada intervenes between the cause of the change and the word containing the n,
The word पदव्यवाय is a compound meaning पदेन व्यवाय 'separated by a Pada'. Thus माषकुम्भवापेन, चतुरङ्गयोगेन, प्रावनद्धम्, पर्यवनद्धम्, प्रगान्नयामः, परिगान्नयामः ॥ Here the Padas कुम्भ, अङ्ग, अव &c, intervening, the change does not take place.
Vart:- It should be stated when there is separation by a Pada, except in a Taddhita. Prohibition does not apply to words like आर्द्रगोमयेण, शुष्कगोमयेण ॥ Here गो takes the affix मयट् by 4.3.145, and the word गो is a Pada by 1.4.17, and it intervenes between मय and the first word. The author of Mahabhashya however does not approve of this Vartika. According to him the word पदव्यवाय means पदे व्यवाय ॥,