If I scan from my HP 8500A using the automatic document feeder and GScan2PDF, the scanner feeds paper but nothing appears in the program (from either side of the page). If I have it scan from the glass, then scanning works, but I have to manually feed pages.
If I scan via hp-scan --adf, scanning works as expected with the automatic document feeder.
Both programs use the same device, Using device hpaio:/usb/Officejet_Pro_8500_A910?serial=CN16HCR00K
Any ideas?