The affix yat (yaṃ) comes in the sense of 'long standing' after the word kāla being the Nominative 1st-Case in construction.,
As प्रकृष्टो कालोऽस्य = कालिकमृणम् \long-standing debt\. कालिकम् वैरम् \long-standing enmity\.
In this sutra काल and तदस्य are understood, but not so the word प्राप्तम् ॥,