Leave Carry Over Not Working

Last year we created the leave policies and we allow carrying over of 5 days but they must be used within the first 90 days of the following leave period.

Most of the staff didn’t manage to take all their leave so when I applied the new leave policy it showed some with an extra 5 days that they could carry over but, as soon as i pressed submit those extra 5 days have been removed, does anyone know if there is a fix for this or experienced anything similar?