Sometimes, you may have company sites that don't use the systems 'Global' time off settings, instead, they use their own. Employee's may have a carryover entitlement but is not showing accordingly via their time off map. This may be the case of carryover for the specific site has expired.
To make sure that employees in the company site do get their entitlement, you must ensure that 'Expiry date for carryover days' is set to a date in the future. To do this you should go to:
Administration -> HR -> Data Management -> Sites
Edit the desired site, if you then go to Holiday year, you should set a date in the future and makes sure 'Expiry date for carryover days' is not set in the current year, instead, is set to a date in future. This ensure that employees within the site get their entitled days for carryover.