[Bug-tar] tar uf -C not working with a directory as input

[Olivier B.]

With tar 1.27.1 (Ubuntu14), I noticed errors in a script that worked
in 1.23 (RedHat6)

CWD is /path/to/script
I used to do
  tar uf /path/to/script/subdir/archive.tar -C /path/to/files directoryA
(in order to include /path/to/files/directoryA in the archive)

But with tar 1.27.1, this does not work. I get
tar: directoryA/file1: Cannot stat: No such file or directory
tar: directoryA/file2: Cannot stat: No such file or directory
So the -C is used since tar can list the files in the folder, but
later they are not found

I can do, (still from /path/to/archive with 1.27)
  tar uf /path/to/script/subdir/archive.tar -C /path/to/files
directoryA/file1 directoryA/file2
and this works

And if i chdir to /path/to/files, then the original command manages to
find the files in the directory

The original command worked from /path/to archive with tar 1.23