BUG: External Monitors Don't Sleep While In ClamShell Mode

[myn]

Background:

While in clamshell mode (Lid closed, power plugged in) and connected to a Dell D3100 DisplayLink dock the external monitors do not acknowledge any sleep commands. However if not in clamshell mode (Laptop Monitor is opened) the internal and external monitors observe the sleep command

Reproduced on:

• 2018 15" MacBook Pro (Intel)
• MacOS 12.1
• DisplayLink Driver 1.6
• Dell D3100 Dock
• 3 HP E223 External Monitors

Steps To Reproduce Bug While In ClamShell Mode:

1. Put MacBook into Clamshell mode (Lid closed, power plugged in) and connect to DisplayLink Dock connected to multiple external monitors.
   
2. Run Terminal and issue the command "pmset displaysleepnow"
   
   Observe no external monitors sleeping.

Steps To Validate Functionality Working As Expected While Not Clamshell Mode:

1. Take MacBook out of Clamshell mode by lifting lid so Internal Display is also on
   
2. Run Terminal and issue the command "pmset displaysleepnow"
   
   Observe all monitors (Internal and External) going to sleep.