mat-select disabled attribute doesn't work in the legacy angular-material?

Question

We have upgraded to Angular V15 but are still using the legacy Angular-Material component. What I've noticed is that the disabled attribute in the mat-select is not working anymore.

<mat-select 
    panelClass="lazyloadselector" 
    (infiniteScroll)="getNextBatch()" 
    [formControl]="appselect" 
    [complete]="offset === tempOptions.length" 
    msInfiniteScroll 
    (openedChange)="openChanged($event)" 
    [disabled]="disabled" 
    (selectionChange)="selectionChangedTrigger($event)">
      <mat-option unselectable="on" [disabled]="true" class="searchselect" *ngIf="showSearchField">
        <input label="Sneltoets ALT+S" class="mat-select-search" type="text" (keyup)="onKeyUp($event)" placeholder="Zoeken..." #input (keydown.space)="$event.stopPropagation()">
      </mat-option>
        <mat-option *ngFor="let option of values$ | async" [value]="option.value">{{option.viewValue}}</mat-option>
    </mat-select>

If I look at the generated html the 'mat-form-field-disabled' is no longer there.

*

Previously (Angular V13) it would look like this

Are other experiencing the same issue or have I done something wrong in the upgrade? The in the html has not been changed.