I have a Dell 9360 Dell edition with Ubuntu 16.04 (kernel 4.8) and latest BIOS and NVM firmware. I have the same issue like mentioned on product page
“(1): We have had reports that in some cases the Dell power adapter must also be connected to the system for stable operation. We are investigating this behavior”
Sometimes dock station starting reconnect frequently if Dell power adapter doesn’t connected.
It’s totally not a big deal to connect an power adapter but if you guys has something to check (beta version of dock firmware or something like this) I would be happy to help with testing.