Precision 7750, USB-C and HDMI monitors with WD22TB4 dock

Last May, my work provided me with a Precision 7750 and two Dell S2722QC monitors.  They also set me up with a WD22TB4 dock.  When we initially connected everything, we discovered that the monitors did not have DisplayPort inputs, just two HDMI and a single USB-C display input.  So, we connected one monitor to the USB and one to the HDMI.

Initially, this didn't work, but we updated the firmware on the dock and magically, I had two working monitors.  I continued this way until a couple days ago when I switched offices.  I unplugged everything and got set up in the new office.  Connected both monitors the same way they were connected in the old office, using the same cables.  Now, I can only have one monitor on at a time. 

If both the USB-C and the HDMI are connected, the HDMI monitor receives no signal.  If I disconnect the USB-C, then the HDMI monitor works just fine.

We double checked all the firmware, but everything is up to date.

I grabbed a different dock (same model), wondering if maybe the dock had gone bad.  Each time I boot my laptop while using the new dock, I get a message saying that USB-C and HDMI cannot be used at the same time.

I understand what it's saying, but I was able to do it without issue for over five months.  What's changed suddenly that is prohibiting me from continuing to do so?

For now, I found a DisplayPort to HDMI converter and have connected the HDMI monitor into it.  This limits me to 1920x1080 resolution on that monitor, but at least I'm able to work.

Any ideas?