Line in on 2013 UltraSlim Dock not recognizing headset microphone

[SentryOne]

I'm running Windows 10 64-bit on an hp EliteBook 820 G4 docked to a 2013 UltraSlim docking station.  I have a Plantronics .Audio 355 Multimedia Headset which has 2 separate 3.5mm headphone tips.  One is for stereo headphones and the other is for the microphone.  The microphone has 2 rings (perhaps indicating that it is a "stereo" mic).  However, when testing, the microphone does not work in any application (audio control panel, B&O control panel, Skype etc.).  No sound is picked up from the mic at all.  Heaphones work and sound comes through those with no issues.  When the microphone cable is inserted, it does detect the line in but still no mic audio is heard.  I have applied all available updates via the SoftPaq download manager and my Windows updates are all applied.  Also tried slightly disconnecting the microphone to see if it is picked up when only partially inserted.  The microphone was also tested and works with other devices. Any advice for me?

[ThomasvandenEnd]

I have exactly the same problem, the only difference is that I have an Elitebook 850 G3. Is there something wrong with the docking station?

[ThomasvandenEnd]

It's a known issue apparently: https://support.hp.com/nl-nl/product/hp-2013-ultraslim-docking-station/5450893/document/c04352894