Thanks for the reply! Are you using the new 10.5 update that came out in the last day or so?
I've discovered that I can't attach files of any kind- if I try to attach a PDF saved directly to the Android file system to a note, the note just says "Loading..." and never changes, so I don't think the issue is related to CamScanner. The only thing that has changed is the recent Evernote update.
The PDFs I'm testing with are quite small- about 200 KB. My Internet speed is very fast- about 280 Mbps down/up from my phone, believe it or not. I checked to make sure I have plenty of free space on the phone (over 80 GB free) and tried uninstalling and reinstalling the app, but get the same results. The phone is an S9 running Android 10. I'm a heavy Evernote user (at least I think I'm a heavy user, but who knows- about 16,500 notes), so I wonder if that has something to do with it?
I would happily revert to the previous version, but I'm not sure that's possible. This has really impaired my workflow.