I didn't know there were APFS-formatted disk images (new in 10.13). Even when you consider the many different kinds of disk images that macOS supports, there's a pretty clear distinction between disk image and a backup of your startup disk, made to another partition in another drive.
Any additional clarification would get into "MacOS may lose data on APFS-formatted disk images (disk images, not disk-to-disk, as in another volume..." territory.
"may" lose data on "APFS-formatted" disk images.
I back up every day to my Synology NAS for example.
How do you like your Synology NAS? I’m considering it.
RAID (including the software RAID in Linux) doesn't actually do checksumming for file verification. AFAIK, ZFS is the only open system to do so.
The title is very clear, and the first paragraph which you quoted explains it in detail.
It's significant that an established respected company--the makers of Carbon Copy Cloner--will not support APFS formatted disk images for its backups.
While your agenda may be driven by the need to protect Apple, the rest of us need to know this important news about APFS so we can be fully informed.
People can have opinions without them needing to be flagged as having hidden agendas. And I have worked at Apple and can assure you that there isn't some payment structure for posting on forums.
What I describe below applies to APFS sparse disk images only — ordinary APFS volumes (e.g. your SSD startup disk) are not affected by this problem. While the underlying problem here is very serious, this is not likely to be a widespread problem, and will be most applicable to a small subset of backups. Disk images are not used for most backup task activity, they are generally only applicable when making backups to network volumes. If you make backups to network volumes, read on to learn more.