While the days will accrual month on month the Carryover Event will remain an annual occurrence.
There is still a defined carry over event date for monthly cycles, this is established when the policy is setup in the cycle settings under the "allowance" step.
The "annual carryover and "grant date" will display the date when the carry over event will take place.
Note: when a carry over event is due to take place, but it is in the middle of a cycle, the event will take place at the start of the next cycle.