iCloud Pages Documents data loss

I use iCloud Pages a lot, on my iMac, iPhone, and an old MacBook. On Wed. at bedtime, as usual, the last thing I did with a device was to set up the phone for the night. I did not use Pages. Sometime during the night I glanced at the time on the phone and saw a message that said something like “This document was deleted at another location”. In the morning I discovered that an important iCloud-hosted Pages doc was gone. Short story - completely gone! I spoke to an Apple support tech who marched me through every possible “place” it could be, both within the devices and online, including online deleted files search. Nothing! She was mystified… Unless I sleep-walk deleted the file (I have no history of such things) I did not do this. So…glitch or hack?

[Re-Titled by Moderator]