External monitor connected via Thunderbolt 3 dock flickers

I have a MacBook Pro 13-inch 2016 w Intel Iris 550. It's connected to an OWC Thunderbolt 3 dock. I recently purchased a Dell U2717D monitor and connected it to the dock via the included DP to mini DP cable.

The monitor works, however, I get a very slight flicker on the lower part of the screen on occasion. The image doesn't switch off, it just jumps very briefly horizontally.

I tried resetting the SMC, but had no luck. Any thoughts?