Full-time salary despite part-time work?

Hello Community,
One year after my parental leave, I have now started working part-time again.

Now my gross salary has also changed. Since the part-time contract was sent to me relatively late and I was only able to submit it the week before last, I received my full-time salary this month. Is it possible that the payroll will deduct the unworked salary from my paycheck?
Please help – thank you very much.