Angular Material DatePicker showing calendar below date field

I am trying to implement a basic date picker inside a dialog exactly as described in the documentation but it does not show the calendar icon correctly. Here is how it looks like:

Here is the html template code for the dialog:

<div class="dialog-header">
  <button mat-icon-button tabindex="-1" (click)="cancel()">
    <mat-icon>close</mat-icon>
  </button>
</div>
<div mat-dialog-content>
  <mat-form-field appearance="fill">
    <mat-label>Choose a date</mat-label>
    <input matInput [matDatepicker]="picker" />
    <mat-hint>MM/DD/YYYY</mat-hint>
    <mat-datepicker-toggle matIconSuffix [for]="picker"></mat-datepicker-toggle>
    <mat-datepicker #picker></mat-datepicker>
  </mat-form-field>
</div>

And here is the css code:

:host {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.dialog-header {
  display: flex;
  flex-direction: row;
  margin: -10px -10px 10px;

  & > h1 {
      margin: auto 0;
  }

  & > .mat-icon-button {
      margin-left: auto;
      margin-bottom: auto;
  }
}

.mat-dialog-content {
  width: 100%;
  display: flex;
  max-height: unset;
}

I have already tried to remove almost all CSS of all container components but it does not matter, the datepicker is always displayed with this broken layout. I also have no global styles or anything else that could cause this, so I am completely clueless about what is going on here.

I just noticed that I was looking at the wrong documentation (15.1.0-next.0). In that version, matIconSuffix was used instead of matSuffix like in previous versions. After changing matIconSuffix to matSuffix in my code, the problem disappeared.