[Patch 3.15] Borderless Windowed mode causes frame rate drop in outside videos

First I load FFXIV in borderless window mode. Then I start playing a video in youtube / windows media player, and now all videos drop to 5-10 frames per second whenever FFXIV application has focus. If I take focus away from FFXIV the frame returns to normal, and I've never had this issue till this week.

1) I'm not sure is this is as a result of the recent FFXIV patch or the recent Windows 10 patch.

2) If I set FFXIV application to Windowed or Full Screen mode the issue does not exist. It only exists in Borderless Windowed mode.

3) I have tested this with other games and have not been able to repeat the issue.

Edit: This is a dual-screen setup

Solved: Windows 10 pushed another update across that fixed this issue.

Update: Only Semi-Solved: The issue does persist, but there is a work around. You have to start by setting the game to full screen mode, THEN set it to borderless windowed mode and it fixes the issue.

Nvidia driver update on Monday the 21st fixed the issue.