The word pati when used in connection with a noun ending in the 6th or genitive case, is ghi , optionally, in the chandas (Veda).,
The word pati is understood in this sutra. By the last sutra, pati would have not been ghi when not in composition. This sutra makes an exception to that when this word occurs in the Vaidic literature.
कुलुञ्चानां पतये or पत्ये नमः salutation to the lord of the Kulunchas.
Why do we say 'when used in connection with a noun in the genitive case'? Observe मया पत्या जरट्टषिर्यथासः.
Why do we say 'in the Chhandas'? Observe ग्रामस्य पत्ये.,