Discovered this bug :( in my Ubuntu 16.04. Workaround I use - configure "window spread" on one of the corners using Unity Tweak Tool and just briefly move mouse in this corner twice.
Actually, I configured "window spread" action corner just since I like this and only later found that this works as a workaround for given problem.
Meanwhile this bug is officially known since 2 years already.
I just checked posts history and found that this is just the second post about Ubuntu, meanwhile Ubuntu is my primary home laptop OS. I'm surprised.