Serious bug in Sonoma 14.4 will destroy saved versions in iCloud Drive

Is your Mac running macOS Sonoma 14.4?
Do you save documents to iCloud Drive?
Do you have Optimise Mac Storage turned on?

If your answers to all of those three questions are yes, then be aware that files that you save to iCloud Drive are at risk of losing all their saved versions.

I’m very grateful to JK, who has alerted me to what I can only assume is a serious bug in 14.4. In previous versions of macOS, when a file is evicted (‘Remove downloads’) from local storage in iCloud Drive, all its saved versions have been preserved. Download that file again from iCloud Drive, and versions saved on that Mac (but not other Macs or devices) have remained fully accessible. Do that in 14.4, and all previous versions are now removed, and lost forever.

From my previous testing, that certainly doesn’t happen in Ventura, and when I tested earlier in 14.3, that wasn’t what I observed either.

If you value the saved versions of your documents, either:

don’t put them into iCloud Drive at all, or
turn Optimise Mac Storage off, so they can’t be evicted from local storage.

Please report this to Apple via Feedback, particularly if you have been affected by it.