Need to know what PDF driver you're using.
Are you printing directly in the sheet, or printing from Sheet Set Manager?
My experience is if using the OOTB Autocad DWGtoPDF driver and you print directly from the sheet, the layout shows up in the name and haven't figured out how to change that.
If you print your drawings from Sheet Set Manager and use the same driver, it will leave the layout name off and only use the sheet number and title.
Mike Porter
https://provostandpritchard.com/