DisplayLink monitor has reduced color depth

I have the Triple Display USB-C Docking Station connected to a Dell XPS 15 9550 running Windows 10 Anniversary Update. After an initial bumpy start (issues with monitors disconnecting, etc, which Josh in support helped me work through) everything is mostly working great at this point.

However I have two identical 2560x1440 monitors (Acer K272HUL), with #1 connected to the DisplayLink “4K HDMI” port and #2 connected to the “2K HDMI” port. Monitor #2 looks great (though a bit sluggish which is understandable since it’s over USB) but Monitor #1 seems to have a lower color depth and is blocky in places.

For example I’ve noticed the mouse cursor on monitor #1 is blocky (non-antialiased) and doesn’t have effects like drop shadow. It seems as though hardware acceleration may not be working on that monitor, while it is on #2.

This laptop has the Nvidia “Optimus” technology which automatically switches from integrated (Intel) graphics to dedicated when needed, and I’ve tried switching that to always use NVidia but that hasn’t resolved the issue.

I didn’t notice this happening at first, so it may be a recent driver update or maybe I just didn’t see it, but it’s one of those things that becomes very annoying during use. Any ideas?