Microsoft is aware of the issue and is working on a fix for it. For now, there is a simple workaround to fix this for now.
Microsoft : After installing KB5020044, Task Manager might display certain elements in the user interface (UI) in unexpected colors. On affected devices, Task Manager should function as expected but some parts of the UI might not be readable. You might be affected by this issue if you have “Choose your mode” set to “Custom”, in the Personalization -> colors section of Settings. If you are using Dark or Light for the “Choose your mode” setting, you should not be affected by this issue.
Workaround: To mitigate this issue, you can set the “Choose your mode” setting to either Dark or Light until this issue is resolved. To do this, right click or long press on the desktop, select “Personalize“, select “Colors“, and then select either “Dark” or “Light” for “Choose your mode“.