There is no specific setting in Payables that causes the advice to print double spaced.

Did this just start happening? If so what changes were recently made to the cheque specification?

Try editing your cheque specification (Maintenance | Maintain Specifications) and check the Advice Detail section. Is there white space below the data fields? Then click on the Advice Detail title bar, then right click, and then click on properties. Set the section height to 0.1667 (the height of a line).

Not sure how to go about doing this then you may need the assistance of your Adagio Consultant.