Set the Carry Forward Leave to Never Expire
In carrying forward leave, when you set the carry forward to"Never Expire", the New year leave balance should be added into the existing balance instead of disabling the old ACF balance.
Before doing so, the leave type must be created and the limit to carry forward must be defined. Below are the user guides for your reference:
Step 3
On the leave type details, scroll down to Carry forward. Toggle the Yes button for “Allow balance leave to be carry forwarded to next year?”