It appears that while framing a policy on employee leave, you have not defined what is prefix and suffix. Sundays and Closed Holidays can be either prefixes or suffixes.
Any Sunday or Closed Holiday that falls before the leave is called a prefix and if it falls after the leave is called a suffix. Neither you can deduct salary for prefix or suffix nor can it become leave itself.
For the case at hand, 15th, 16th & 17th Oct 2021 will become suffixes.
From India, Bangalore
If the company decides against allowing CL on 14th October, in exigencies of service, leave can be denied. It is a call to be made looking to all the factors
From India, Mumbai