Annual leave is an entitlement. The purpose of annual leave is to sustain initiative and enthusiasm and to encourage the physical and mental wellbeing of CF members by providing periodic opportunities for rest and relaxation.
As a fundamental key to sustaining good performance, COs shall establish leave plans which will ensure that the entire complement of annual leave is granted with due consideration given to IMR.
Annual leave does not have to be earned before it is used; however, over expenditures of annual leave shall be recovered.
The annual leave entitlement for members of the Regular Force is prescribed in QR&O 16.14(4) and is summarized as follows:
a member of the Regular Force with less than five years of service in the Canadian Forces is entitled to 20 working days annual leave per fiscal year;
a member of the Regular Force who has completed at least five years of service in the Canadian Forces but less than 28 years of service in the Canadian Forces is entitled to 25 working days annual leave per fiscal year;
a member of the Regular Force who has completed at least 28 years of service in the Canadian Forces is entitled to 30 working days annual leave per fiscal year; and the annual leave entitlements in the year a member enrolled in, transferred to, released from or transferred from the Regular Force is calculated in accordance with QR&O 16.14(4).
and also do not earn annual for periods of LWOP. So if you are on LWOP for 6 months of the FY, you won't receive full yearly complement of annual leave. Your annual entitlement would then be reckoned at 1/15 days or 2 annual per month for each month you are working (3 days for the last month of the FY for those entitled to 25 days annual per FY). All of those days should be credited to you upon a return from LWOP without actually having to work 15 to earn one etc.
This may be a case of a CoC expecting an individual to be released in short order, and thus not wanting the individual to take leave in advance of it being earned to avoid having to take recovery action.
But being unable to talk this over with the individual or their CoC, it's just a guess... like most of the conversation in this thread...
If you have been in for 5 years or more, you are entitled to 25 days annual leave per year.
That said, if your chain of command feels that a release is pending for you fairly shortly, they might be trying to do you a favour where you don't owe the CF days of leave you that over expended and then have to pay back. For example, if your release comes in before the end of this Fiscal year (31 Mar), your leave entitlement for the year retroactively becomes 24 days (2 days/month) not 25 days for the year.
If you were to submit a leave pass for short leave, that would cost you nothing. COs can grant 2 days/ month.