Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

@angular/material 18.1.0 did not have this behavior

Description

Hi,

I am using NVDA v2025.3 (latest version) for accessibility testing and have noticed that the mat-error presentation is announced twice by the screen reader.

The above example demonstrates the issue from the angular material docs:
https://material.angular.dev/components/form-field/overview#error-messages

Reproduction

Steps to reproduce:

1. Open screen reader and set focus on an angular material mat-form-field with mat-error presented on blur
2. Tab away from the field to trigger error message presentation
3. Observe announcements and notice that mat-error text is read twice.

Expected Behavior

mat-errors should only be announced a single time by the screen reader.

Actual Behavior

mat-error is announced twice by the screen reader.

Environment

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