Trending @HCL; Query on GHMI/Medical insurance premiums

I joined on Aug 1st IN HCL. Medical insurance deducted approximately 10k rupees as arrears and recovery in September salary, 23k deducted in October for medical insurance.

My ququestion, are medical insurance premiums deducted from every month's salary or only once in an year?

The policy hub says both statements. I.e. 1. every month and 2. only the upcoming month. Not sure, what is correct.

Please help with your answer. Many thanks in advance.