There is vocalisation of śyā preceded by the upasarga prati , when the niṣṭhā affixes follow.,
Thus प्रतिशीनः प्रतिशीनवान् ॥ This sutra applies to cases where the words need not have the meaning of \coagulation\ or \cold\.,
प्रतेश् च
Adhyāya 6 · Pāda 1 · Rule 25