DPI to 288 or Lower + Expanded Desktop Glitches Settings
Setting phone DPI to 288 or lower in Expanded Desktop mode glitches the nav bar.
The black bar in the sceenshot is where the nav bar is supposed to be, but hidden because of Expanded desktop. This is most likely a padding problem due to the interface shrinking from the DPI modifications.
I can confirm this is not a Expanded desktop issue, since Cyanogenmod and Xposed produces the same issue. Setting DPI to factory default (480) will not produce this error.