Hi, everybody!
Wanna bump this thread. Have the exact same setup (MBP 2018, Dell D6000 Dock and Dell S2417DG monitor) with exact same problem. HDMI connection only work fine, no signal via DisplayPort. Maybe macOS Support Tool output will be helpful for DisplayLink Team for problem solution?
Sorry, attached file in another thread -
https://www.displaylink.org/forum/sh...5&postcount=17