I just emailed the site for Roma Pass to make reservations for Borghese Gallery and received an email below:
Dear Customer, we inform you that the agreement between Roma Pass and Galleria Borghese is no longer active.
For this reason, reservations using Roma Pass are no longer accepted.
Please visit the www.tosc.it website or call number +39 0632810 to buy the tickets
Make sure you note this if you were planning on using the Roma Pass to access Borghese Gallery.