The affix ghañ comes after the roots 1. śṛ 'to go to' 2. nī 'to lead' 3. bhū 'to be' when not in composition with an upasarga ,
This debars the affix अच् 3.3.56. As श्रायः 'shelter', नायः 'a means', भावः 'a condition'.
But with upasargas, we have प्रश्रयः 'respect', प्रणयः 'love'; प्रभवः 'source'.
How do we explain the form प्रभाव in प्रभावो राज्ञः 'the splendour of the king'? Here the word प्रभाव is not made from the compound root प्रभू + घञ्, but by compounding प्र with भाव by the rules of samasa, meaning 'excellent condition'.
How do you explain the form नय in नयो राज्ञः ? Here the root नी has taken the affix अच् diversely by 3.3.113.,