IngoW - Thank you for sharing. That is good to know. We are planning on testing the 1809 roll out this summer, so if this is the permanent fix, that will be great!
I did want to share a temporary fix that has gotten us by for now. You're right, it's a Windows issue, but it's also a Dell docking station issue. There appears to be a communication problem with the netbios between the dock and the Windows PC. I have no clue what I'm talking about beyond that, so that's all I'll say.
I had all effected users run this fix siliently. https://github.com/filippobottega/ShareFix/blob/master/README.md They must be docked to their main docking station when they run it.
It rebuilds the binding of the network adapter interface. Basically it fixes the communication between the Windows pc and the Dock Nic adapter. The only issue with this is when they use a different dock, it breaks the communication again. Luckily, it reconnects when they go back to their home dock. Maybe someone who knows what they are talking about can explain this better.
We have 700 users and this issue was effecting around 100 of them, so it was substantial. I'll look forward to the 1809 update as well.