I have a very similar issue. I bought the USB-C 4K docking station. I have the same HP Spectre x360. The dock worked fine up until a few weeks ago. Then the displays would then freeze, then turn off and on. Lastly earlier this week the HDMI monitor stopped working. Now last I checked the Dock works with my other Dell Latitude laptop, but I purchased this specifically for the HP. I followed the instructions that were posted where you would uninstall the display link then re-install but this did nothing to help the issue.