There is an bug in VP14 Build 189 also:

I have monitor 1, a UHD-monitor, on HDMI 2.0 of my graphic card (AMD Radeon 480 8GB).
And monitor 2, a FHD, on HDMI 1.4 of my board (I7  Z170.

I works with Vegas Pro 14 on monitor 1.
Monitor 2 should be the preview monitor.
As soon as I click on the preview monitor button VP14 crash immediately.