Unity does not reappear if window is snapped to the left side

If you move a window to the left side of the screen and it resizes to half size of the screen (grid) and unity is set to autohide, unity won't reappear if you move the mouse to the left side.

Two ways to show the launcher again:
1. Pressing the Super-Key shows the launcher.
2. If you move the left-snapped window a litte bit to the right and then try again showing Unity with your mouse touching the left side, it works.

Expected behavior:
Launcher should reappear as always on moving the mouse to the left side of the screen.

What happens instead:
Nothing.

System:
Ubuntu 16.04 LTS

Version of Unity:

unity:
  Installiert: 7.4.0+16.04.20160526.1-0ubuntu1
  Installationskandidat: 7.4.0+16.04.20160526.1-0ubuntu1
  Versionstabelle:
 *** 7.4.0+16.04.20160526.1-0ubuntu1 500
        500 http://de.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     7.4.0+16.04.20160415-0ubuntu1 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/main amd64 Packages