External Monitor Blinks

I have a latitude e7470 running windows 10 running version 1909 of windows 10 and was just updated. I plugged it into a dell dock which is using a displayport to hdmi cable. It connects via the dell pro2x usb 3.0 docking station to a dell e2318hr monitor. Every few minutes the monitor would go black for a few seconds. I uninstalled the intel hd graphics graphics 520 driver and restarted. It didn't help. I tried installing the driver for this monitor, it didn't help. Also all my drivers and windows 10 have been updated today.

I have another monitor connected to the dock. I activated the second monitor which is a Hewlett Packard 27er 27-in IPS LED Backlit Monitor. So, my first monitor at first was fine, but now the second monitor blinks. However the first monitor will still blink once in a while, much less than it did before hooking up the second monitor.

Today, I had a latitude e6440 hooked up to this dock and had no problems at all. It only started to blink with the latitude e7470 which just had a clean install today. I had previously used the dell power manager on the e7470 to reduce the maximum battery charge but it turns out, it is supposed to be incompatible with this computer. I also had that running on the latitude e6440 with no problem. I also took bit defender off this computer (I don't know why that'd be relevant but one web site I found said virus software could be a problem).

This i set up is new to me. I just installed an nvme ssd and a new battery.

 

Well, I've researched this and tried a couple of things to no avail. While I still have a return window on this computer, I am sending it back.