The prātipadika (Nominal Stem) yuj before the strong cases gets the augment (num) n when it does not stand in a compound.,
Thus युङ् 8.2.23, 8.2.62 युञ्जौ, युञ्जः; but अश्वयुक्, अश्वयुजौ, अश्वयुजः in a compound. The root युज समाधौ (Divadi 68) is not to be taken here; therefore not here युजमापन्ना ऋषयः ॥ But युजिर् योगे (Rudhadi 7) is to be taken.,