Last synced mod time for item 1/25MMGAFI doesn't match time on storage server but hash does -- ignoring
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Yes, I'm talking about syncing. I can see the progress in the upper right corner, when hovering. It goes down to 0 and then starts over with the same ~2000 left.
If it's happening right now, can you provide a Debug ID for a few minutes of it?
I think we can handle this state better, but in the meantime you can see what happens if you use Reset File Sync History (and nothing else) from the Sync → Reset pane of the preferences. That may not fix it, but there's no harm in trying.
I've removed Zoo (so as not to accidentally open it while debugging), disabled BBT, and restarted in debug mode. Let's see what happens. Now it's syncing over 2500 items.
In addition to the possibilities there, it could happen if a Zotero client uploaded an incorrect timestamp to WebDAV (e.g., based on seconds instead of milliseconds).
(After this fix, it will be harder to know that it's happening, though there'd still be some extra sync activity.)