So right now, after reinstall, suspend seems to work a bit better. Kernel is
4.4.0-140-generic. When I try suspending from the main menu (using KDE), the
same problem occurs.
But when closing the lid the notebook goes to suspend after a short period of
inactivity and wakes up immediately after opening the lid again. Fortunately,
this does not happen while on the docking station, so I don't have to keep
the lid open all the time while it is sitting on the dock.
At least I think it is going to suspend when lid is closed. The moon-shaped
LED turns on, which I suspect is supposed to indicate suspend, or maybe
hibernate? Who knows.
That's exactly how I would expect the notebook to perform. Not suspending
while sitting on the dock with closed lid, while disabling the screen and
suspending if the lid is closed while running on battery power off the dock.