Here is an other idea if you are not using Actions for Vacation Leaves.
You could create a special "Back from vacation" Attendance to enter on the first day after a vacation.
Then, create a Time Evaluation PCR to check if there was a Vacation Absence "Yesterday", and if the answer is YES, check if the "Back from vacation" Attendance exists today.
- If there was no Vacation Absence yesterday, proceed as usual;
- If there was a Vacation Absence yesterday and there is a "Back from vacation" Attendance today, proceed as usual`
- If there was a Vacation Absence yesterday but no "Back from vacation" Attendance today, generate error.