To correct this behaviour, delete the initial absence request and split the holiday into two separate requests, one for each month.
You will need to check the holiday entry to ensure that what has been booked does not contradict the days. Half day holidays can only be inputted for half of one day, so they cannot span over two days; this will cause the planner to shift working days. You will need to remove the holiday and add this back with the correct values.
If the above wasn't helpful, refresh the planner:
Click Access Button
then click Employee.
Click Planner then Settings.
Select or unselect Entitlement includes Public Holiday.
Add a reason for changing the setting.
Click Save or to revert to the initial set-up, repeat step 2.
In addition to the above, unassign the public holiday template and then re-assign the template to them.
📌Note: You need to use the same effective date for the public holiday template.