Hello. I recently purchased the UD-ULTCDL docking station. I used the UD3900 for about a year with this same laptop (2018 HP X360 Spectre 15T (product #1VW22AV) but wanted both of my external monitors to be at their max resolutions (4K and 1280x1024) and the UD3900 would only allow the HDMI at 1920x1080 over USB 3.0.
Anyway, I plugged in the UD-ULTCDL and everything was working as expected for about 48 hours until the 4K HDMI port stopped working. It still shows as connected in windows display settings but the screen is blank (the DVI monitor is working fine.) I searched the forums and found other references to this same problem and unplugged and then plugged in the docking station and everything worked fine again for another day.
I shouldn’t have to unplug the device every day in order for it to work properly. Is there a driver or firmware fix for this? Please advise before I return the item!
** Update - I have noticed that the 4K port doesn’t work after the computer goes into sleep mode. If I unplug the power from the dock and plug it back in, everything works. **