I suggest you to post these kind of inquiries in the future into the Intel(R) Desktop Boards support forum for to expedite your concern.
Concerning this issue, please let me know, what happens if you only test the ViewSonic VA1912w without the other monitor being connected?
While troubleshooting this, be sure to be using the latest BIOS of the motherboard, the and load the latest inf driver of the ViewSonic monitor. Do not use a ny type of adapters or converters while testing this.
And please copy-paste the graphics report generated within the Intel® Graphics User Interface while the ViewSonic display is connected. For information on how to retrieve this report, please visit the following page: