Recently, I wanted to check that some newly added files are present in my latest attic backup and to that end mounted the latest backup to a local directory (attic mount). To my surprise, the files in question where not present in the mounted archive. I picked one particular file that should have been present and tried extracting it through attic extract and to my even greater surprise, the file was extracted correctly. Here is the exact series of commands I entered (as root user):

$ mkdir /tmp/attic
$ cd /tmp/attic
$ attic extract $ARCHIVE media/sync/kischd/home/kristiane/.xsession-errors
$ ls /tmp/attic/media/sync/kischd/home/kristiane/.xsession-errors
/tmp/attic/media/sync/kischd/home/kristiane/.xsession-errors
$ mkdir /media/attic
$ attic mount $ARCHIVE /media/attic/
$ ls /media/attic/media/sync/kischd/home/kristiane/.xsession-errors
ls: cannot access /media/attic/media/sync/kischd/home/kristiane/.xsession-errors: No such file or directory

I expected that both methods allow me to access said file. If this is the case, then something is wrong and should be fixed, as attic mount is my preferred way to verify that certain files have properly been backed up.

Let me know if I can provide additional information or assist in any other way.