So I got a replacement machine on Tuesday because of the coil whine issues I've been discussing in another thread, and after restoring my Time Machine backup, the display connected to the Pro Dock was set to 30Hz and couldn't be changed in System Preferences. I disconnected the machine from the dock and zapped the PRAM, which worked for me.
Since I don't know your exact setup, and if I was troubleshooting, I'd also try connecting the power adapter to the machine, as the dock cannot provide a full 96 watts of power the system's rated for. So it's possible the system's underpowered.
Have tried this
Don't blame the computer, it's the shoddy docks.
its not the dock because i've tried to connect both the original 96 watts power adapter and the external display connected directly through USB C - Displayport , same flickering problem remains.
Also have reset NVRAM + SMC before connecting external display, no luck.