Assign AD Group to users failing

While we are adding AD privilege thru UI to user which is already activated in AD, we are getting error in 'AssignUserToADSGroup'.

Here is the destination value of the pass:

dn --> $FUNCTION.sap_core_getGroupACCOUNTFromPrivilege(%MSKEY%)$$

changetype --> modify

+member --> $FUNCTION.sap_core_checkAccountAttributeValueExists(%ACCOUNT%$rep.$NAME%%)$$

attached is error screenshot