I have the laptop docked with the ethernet plugged in to the back of the dock as well as a keyboard and mouse. When I disconnect the ethernet, the mouse and keyboard stop responding to my input.
I have updated all drivers and downloaded dock drivers as well. Updated BIOS. Any ideas?
There's a firmware update for the Ethernet controller on the TB16 and WD15, fyi. Go to support.dell.com, click Choose from all products > Accessories > Docks > TB16 > Drivers and Downloads, and you'll find it there.
If that Ethernet controller firmware update doesn't work, a few systems recently got BIOS updates that introduced connection instability for USB devices attached via the TB16. Dell has fixed that and at least some systems (such as the XPS 13 9360) have even NEWER updates that resolve that issue, but it's possible some other systems are waiting for updates to fix that recently introduced issue.