Reproduction

Use StackBlitz to reproduce your issue: https://stackblitz.com/edit/chips-autocomplete-required-failure?file=app/chips-autocomplete-example.ts

Steps to reproduce:

1. Fork the mat-chips autocomplete example from the Angular documentation
2. Move the form control to the mat-chip-list and add required attribute
3. Try using the auto complete 💥

NOTE: Followed suggestion in the following issue to add the required field, but that example doesn't include autocomplete. With this the autocomplete breaks. #14195

Expected Behavior

The autocomplete should filter results based on text entered.

Actual Behavior

The autocomplete does not filter the results based on the text input from the user.

Environment

• Angular: 8.2.14
• CDK/Material: 8.2.3
• Browser(s): Chrome 81.0.4044.138
• Operating System (macOS): Mojave 10.14.6