Are you backing up the project folder to One Drive? If so may be a sync issue. Backing up a zip backup to One Drive should be fine, but if the project folder is set to back up there, then that may be the issue and the troublesome project folder may not be fully synced or have a sync error.
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My guess is that this is a problem with creating a ZIP file. If you backup without saving as a ZIP file, do you encounter the same issue?
For the record, this is my hypothesis because if you try to open a zipped Scrivener backup directly without unzipping it first, you’ll get a slightly different error about the project not being available, including the AppData/Local/Temp string.