Sorry for the late respond; thank you for your patience.
We could reproduce this with the same environment (Win7/Office2013-32bit) with the same version (15.1.1900). We checked the latest version, and the bug was not reproducible there. Then we checked if a related bugfix could fix this issue as well in the meantime, and it seems that it has been fixed in version 15.5.2500. So if you upgrade to any later version, the Absolute labels will be displayed fine.
Sorry for the inconveniences.