The profile for the dock is initially set to Digital stereo (S/PDIF) output
and audio changes when profile is switched to Analog Stereo Output
But what has me really puzzled is that there does not appear to be any digital S/PDIF connection available on this device
There only appears to be one analog audio jack for headphones, headset or microphone
And online data scans for this device only show an analog output (PCM) and microphone input
Lenovo ThinkPad Thunderbolt 3 Dock USB Audio
Card sysdefault:2 'USB'/'Lenovo ThinkPad Thunderbolt 3 Dock USB at usb-0000:08:00.0-2.1.1.2, full speed' Mixer name : 'USB Mixer' Components : 'USB17ef:3083' Controls : 6 Simple ctrls : 3 Simple mixer control 'PCM',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'Mic',0 Capabilities: cvolume cvolume-joined cswitch cswitch-joined Capture channels: Mono Limits: Capture 0 - 30 Mono: Capture 30 [100%] [0.00dB] [on] Simple mixer control 'Auto Gain Control',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [off]
There are no controls for IEC958 digital audio, so it appears that this dock does not support digital audio over the HDMI or Displayport sockets
If you are using headphones or speakers plugged in to the audio jack you should probably be using the profile Analog Stereo Output