As no-one from HP is replying to this topic, I thought I would help anyone who has googled this problem, as I did, and found this post.
I have exactly the same problem, and could not have described it better than the OP. I called HP directly, who are apparently aware of the issue. They are blaming a recent Microsoft security update. They have no timetable for a resolution. It seems to me that HP are content to blame Microsoft, and Microsoft are saying it is up to HP to fix an issue with their printer. In the meantime, the customer is caught in the middle.
The workaround is of course as the OP described: use the HP App on the desktop/laptop and scanning via ADF works. Not ideal.
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