Error WS123 in Tcode WB2R_SV - Contract Settlement

I am settling a Commission Contract via WB2R_SV for and Vendor (External Agent) and getting the error WS123 "A balance of CURR XXX.XX exists in document 0000000001".

Please note that this is for S4Hana 1809.

I have already checked out OSS note 1434621 and it is not applicable.

Any help will be appreciated.