this is remittance advise generation during payment run

i can see a concurrent request "send Separate remittance advice" get triggered when payment run is given. this request takes delivery mode (email/fax) from supplier/site and generates remittance advices using config file "xdodelivery.cfg".

i can ALSO see a "AP Remittance Advice" workflow triggers and sends email notifications using workflow mailer (i can see records in WF_NOTIFICATIONS table for each payment)

Is it generating 2 remittance advices to supplier ?

Separate Remittance advice would be launched automatically if your payment profile is configured such way. You specify your preferences on Reporting tab on Payment Profile screen. Remittance advice is sent to the vendors notifying them that the invoice is paid.