The organization I work for uses Lenovo Thinkpads and we purchased Lenovo USB C docks for those laptops and on the two of the new Gen 11 Intel laptops and on the Gen 8 Intel laptop using three separate Lenovo ThinkPad USB C Docks specifically the Type 40A9 and Type 40AY. The laptops when docked and started from a cold boot or a reboot have an issue showing the screen on the monitors connected with DisplayPort. I don't have HDMI monitors so I can't use HDMI.
This seems to be a well known issue with Lenovo laptops and Lenovo USB C Docks you can reference the sources below. This issue has been going on for about 6 months and I have tried all the fixes listed below during the 6 months applying the fixes as soon as they were available.
The screens are either not showing (just black after about 1 to 3 minutes) or the screen is distorted with running horizontal lines showing only on one screen with screen jitter.
In fact the issue has persisted; with some staff using the devices becoming upset that this issue has not been fixed. I can't say I blame them, we have been using Lenovo laptops and docks for 8 years and just within the last 6 months this has become an issue that hasn't been resolved. At least until today with a work around using powershell. Troubleshooting this issue nothing really came up in the event viewer; I caught an issue with the UCM-USCI ACPI Device not responding and given a error 43 but the dock had not stopped working with the exception of the displays. At least according to the computer management console.
View in device manager
Code 43 given randomly
I had noticed Network, sound, keyboard, webcams, mouse all continued to work when the monitors did the "blinking" issue.
Lenovo L15 Gen2 blinking issue on Type: 40AY Dock
For what ever reason when the monitor "Blinks" stops working and stay black until you either unplug the dock and plug it back in or you disable and re-enable the Intel display driver.
So my solution (after making sure everything was as up-to-date as possible with the latest Lenovo fixes) was the following.
Two Scripts. A bat file and a powershell file.
The bat file allows the running of the powershell script.
Using Task Scheduler, On a user login; I have a script that runs after a 30 second wait to run; However once it runs the script disables the Intel Driver and re-enables it after 10 seconds.
This has stopped staff from having to unplug and re-plug in their laptops into the docking stations; and are much more happy with going to get a coffee when they login then come back then having to unplug and re-plug in their laptop dock.