Macbook Pro 2018 and Dell U3818DW - intermittent connection problem

Hi!

I posted a question about this on a Dell forum. A Dell employee then suggested I also post my question here, since the problem may be due to an incompatibility between the monitor and my MacBook.

If some-one can suggest a fix, I would be hugely grateful ... I'm loving the monitor -- when it's working, that is :-)

My question (cross-posted):  

In Feb '19 I purchased two of Dell's 38" curved ultra-sharp monitors (U3818DW) with USB Type-C connection.

Lately a pretty bad problem has developed with one of them!

 Since last week, when I connect my Apple laptop to the monitor, the connection breaks. What happens is: I type on my external keyboard (USB, connected to the monitor) for a bit (less than a minute) and the connection breaks. Then, I type on my laptop keyboard for a bit (using my laptop screen) and the connection comes back.

This cycle happens about two or three times a per minute. 

In fact, it's happening right now as I type this.

I've tried swapping out the USB Type-C cable, but that doesn't help.

I think what may be going on is that the USB Type-C "channel" from the monitor is doing a lot of work -- re-charging my laptop (it's currently at 29%) and also transmitting the USB signal from my keyboard and mouse, which are connected to the monitor, not the laptop. Maybe this is overloading the monitor's ability to transmit and receive both power, video signal, and keyboard signal? Then, when I switch back to using my laptop keyboard, the USB-C cable doesn't have to transmit as much -- just power. When the load lightens, the monitor is able to detect the laptop signal again. When I go back to using my external keyboard again, which is connected to the monitor, the cycle repeats.