Mat Autocomplete With Required Input Flashes Error on Option Select

Bug, feature request, or proposal:

If a mat autocomplete has a required input, the input flashes red/invalid briefly upon selecting an item from the autocomplete. This only happens if nothing has been typed in the input field.

What is the expected behavior?

The input should not flash red if an option is in progress of being selected

What is the current behavior?

The input briefly shows as red as an option is selected

What are the steps to reproduce?

Stackblitz: https://stackblitz.com/edit/angular-vtjbve

Reproduction Steps:

1. Click the input
2. Click an option

What is the use-case or motivation for changing an existing behavior?

Can be confusing for end users to see an error flash like that

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular: 8.2.13
Material: 8.2.3
OS: win32 x64
TypeScript: 3.5.3
Browsers tested: Chrome Version: 79.0.3945.130

Is there anything else we should know?

N/A

Inizia con la riproduzione StackBlitz collegata e segui l’interazione di Angular Material autocomplete e required-input quando si fa clic su un’opzione senza aver digitato prima nulla. Traccia la transizione dello stato di validazione durante la selezione; il lavoro è completato quando la selezione di un’opzione non produce più un lampeggio visibile rosso o di stato non valido nel caso riprodotto.