SAP Message 5J458 - Full-time union worker turned to be NOT Deductible

Diagnosis Both 'Fulltime union worker' and 'Deductible' are checked. A fulltimeunion worker is payed by a union, not by the company. Therefore, it isimpossible to deduct union due from the salary. Procedure System turns 'Deductible' off. If you want to put 'Deductible' on,Please change 'Fulltime union worker' into off.