R/3 RFC Destination password changing when bulk messages came

Hi,

When R/3 system trying to connect XI through RFC Destination.. with XI - PIAFUSER. When transfering bulk data then user locked and also password of that user is changed in RFC Destination of R/3. (This PIAFUSER is the XI user).

PIAFUSER user password is changing frequently in RFC Destination of R/3, when ever bulk files comes from external application. ... Y this password is being changed?

Regards

Ansar.