We have a bit of a mystery, in that one of our users, using a 4.5MB Excel file on a share on one of our two servers (which are mounted via a DFS namespace and use DFSR to replicate) saved a file repeatedly last Friday, and came to it on Monday to find it has not been updated for two weeks and none of her changes were saved.
So far, so 'probably user error'...
However the audit logs, which we collect in a log management solution, agree that she saved the file. What's more, the other file server shows a deleted version of the file in the ConflictsAndDeleted folder, which is consistent with the file being updated and correlates with every log entry for the file being saved.
So all the evidence says the file was updated on the 25th June, but the file is still the version from 16th June.