bug(mat-error): mat-error presentation is announces twice with NVDA screen reader

[charles-stivali-87]

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):

[jgrenvik]

I’m still seeing this issue occur in the latest version. It appears the problem hasn’t been resolved yet, and we really need to get this fixed since it impacts accessibility (screen readers are still announcing the mat-error twice).

[michaelchanna]

I have been able to reproduce this problem as well for one of our Angular projects regarding screen reader announcing the mat-error twice. It happened when we upgraded to Angular v20.

[charles-stivali-87]

The native input associated with the mat-form-field has an aria-describedBy and the container holding the mat-error has an aria-live attribute. It is likely that having both is causing the screen reader to announce twice.

From Google AI:

Conflicting ARIA attributes: Using both aria-live and aria-describedby on an element can cause double announcements, as NVDA reads the description on focus and again as a live region update.

An aria-describedby attribute is generally not required for an error message if the entire error message is already dynamically placed within an aria-live region that announces the change automatically

cc: @wagnermaciel