Error mov 546 O

Hi Friends,

We are using Operation Subcontracting. We have GRN wih a 101 and SAP has done an 543 O for the subc materials . Now i have to cancel the GRN , which i am doing through MIGO using 122 Mvt Type , but while cancelling its make an 546 O movement despite of a 544 O. Why is happening this?

Thxs