Can you provide a Debug ID (different from a Report ID, which you provided) for a sync that produces this error?

That's still a Report ID. Follow my link for instructions.

(3)(+0000160): HTTP GET https://[…]@[…]/dav/zotero/CSXIAD37.prop succeeded with 200

(3)(+0000000): <properties version="1"><mtime>1701083259646</mtime><hash>undefined</hash></properties>

There's an invalid value in the CSXIAD37.prop file on the WebDAV server. That shouldn't break syncing, so we'll fix that, but for now you can delete that file manually on the WebDAV server.

You can paste CSXIAD37 into the Zotero search bar in All Fields & Tags mode to see the PDF file in question. To force that file to be reuploaded, you may need to do a Reset File Sync History from the Sync → Reset pane of the Zotero settings on the computer where that file exists.

I'm not sure what caused the invalid file to be created. Could be a plugin you have installed, or could be some bug in Zotero. We'll see what we can find.