Comment 5 for bug 1605833

Unfortunately, I do not see anything unusual. I performed a few tests, but I cannot reproduce your problem.
If I create a direct error, like this:

   touch ~/.test
   sudo chattr +i ~/.test

I get the file name in the error output:

   An error occurred while creating the following hard link:

     /home/.sbuserdata/home/kendek/.test

    Reference file:

     /home/kendek/.test

    /home/kendek/.test
     f rw-rw-r-- 1 1000 1000 2049 0B
   ...

So in your case the Systemback read an empty file name in your home directory, or the file information is damaged. But currently, I do not why. I do not find any related bug in the Systemback.
Maybe try to run an fsck check on your filesystem.