button的Default type是可能导致此问题的submit请尝试将显示/隐藏按钮type更改为button，类似于

<button type="button" mat-icon-button matSuffix (click)="passwordVisible = !passwordVisible" [attr.aria-label]="'Hide password'"
              [attr.aria-pressed]="!passwordVisible">
        <mat-icon>{{passwordVisible ? 'visibility' : 'visibility_off'}}</mat-icon>
      </button>

我最近也偶然发现了这个问题，并能够使用下面的方法解决它。
如果您在密码输入字段中按Enter键，则会调用方法onClickRevealPassword。此操作会导致一个名为pointerType的事件，您可以使用此方法检测该事件，并保持密码字段不显示纯密码值。请查看并使用您的组件进行试验。

<mat-form-field appearance="fill">
  <mat-label>Password</mat-label>
  <input name="password" formControlName="password" matInput [type]="passwordVisible ? 'text' : 'password'">
  <button mat-icon-button matSuffix (click)="passwordVisible = !passwordVisible; onClickRevealPassword($event)" [attr.aria-label]="'Hide password'"
          [attr.aria-pressed]="!passwordVisible">
    <mat-icon>{{passwordVisible ? 'visibility' : 'visibility_off'}}</mat-icon>
  </button>
</mat-form-field>

onClickRevealPassword(event) {
  event.preventDefault();
  // Prevent revealing the password when enter button is pressed.
  if (event?.pointerType) {
    this.passwordVisible = !this.passwordVisible;
  }
}