I just started using the UD-ULTC4K (Plugable USB-C Triple 4K Display Docking Station) with my 2017 Macbook Pro 15". I have it hooked to two displays (HDMI + DP). I am using the included USB-C cable. I have the Displaylink drivers installed. So far, the unit works really well - displays look great and are responsive and the ethernet works.
But the unit is not charging my laptop. It seems like it is providing some charge, because the battery is falling slowly. But it is falling. I checked the compatibility chart here: https://plugable.com/products/ud-ultc4k and it seems like I should be fine - it should be charging. I also tried the charging cable that came with my laptop. NO luck.
When I first plugged it in, I was syncing my dropbox, and the processors were all pegged with the fans on - that’s when the battery was falling. Now that it has calmed down, I see the battery percent rising - very slowly. So, it is charging, but nowhere near what I get with the 87W charger that came with the machine. But I think this will do. I haven’t tried the SMC reset or switching the ports yet.