I'm having the same issue on iOS 15 GM. Scanner version is "1.3" and Encoding Software is "iOS 15.0 (Build 19A346) Quartz PDFContext" Scans look normal before saving (before encoding) but after saving, they get low resolution and really low quality. The output file size is much smaller than before. I haven't scanned documents in notes app before but for now they look better. When I save the scanned document from notes to the files app. The Version and Encoding software are the same and resolution and size are roughly the same. So this means the issue is with scan engine and files app combination. Edit: I'm having this issue on iPad pro 2017 and iPhone SE 2016