Reproduction

Use StackBlitz to reproduce your issue: https://material.angular.io/components/slider/overview

Steps to reproduce:

1. select version v9~
2. click the slider of the demo
3. drag out of the window
4. move back in the window（either release the drag or not）
5. the slider moves with the mouse (even though you did not click the slider)

Seeing mat-slider element in the inspecter at 4, the classes remains such as cdk-focused cdk-mouse-focused mat-slider-sliding.

Expected Behavior

When moving back in the window, focus is released and the slider doesn't move with the mouse.
As if you chose v8 or earlier and did the same in https://material.angular.io/components/slider/overview.

Actual Behavior

focus isn't released and the slider moves with the mouse.

Environment

• Angular: v9~
• CDK/Material: v9~
• Browser(s): chrome
• Operating System (e.g. Windows, macOS, Ubuntu): macOS