Unsolicited duplicate scanning when using HP Office Jet Pro 9020 automatic feed

[iTunesbug]

It's been a couple of weeks that my scanner has been malfunctioning all of a sudden when using the automatic feed and the standard MacOS print application : while each page is properly scanned, the scanner  generates two identical and hence duplicate scans for each page starting  with the following funky numbering system increment (single side scanningn this example: duplex makes things even more maddening):

• the first page will go as "scan 1.jpg";
• then page two will automatically generate two identical scans labelled "scan1.1.jpg" and "scan 2.jpg";
• page three will also generate two identical scans labelled "scan 1.2.jpg" and "scan 3.jpg";
• page four will generate two identical scans labelled "scan1.3.jpg " and scan 4. jpg".

If I scan a new batch of documents from there, it will then pick up with the following double numbering:

• new document page one as "scan 5. jpg";
• new document page two as  "scan 5.1.jpg" and "scan 6.jpg", both identical;
• new document page three as "scan 5.2.jpg" and "scan 7.jpg";
• and so on and so forth

when using duplex it's even more maddening (I won't try to detail the increments at this stage of my exposé).

I have of course restarted my Mac as well as the HP2020. Usually the problem does not come back at once with the first document but shortly after with the later ones. Ain't that crazy? Has anyone ever bump into this before?

Thanks for your thoughts and assistance