IoJK annexation, by India, was carried out in late 1947; when, what to talk of ISI, even Pakistan army was in the process of making and was only partially functional.
In any case, to keep eye on the enemy's intentions, and the movement of its troops and assets, is not the job of ISI. These functions are carried out by other agencies, which are part of military establishment. ISI is an organization, detached from military.
If I correctly recall, you in one of your past posts, told that you are some sort of university student, trying to learn things from PDF.
Keep on learning.