Angular 4 - Reactive Forms - Blurring one field highlights all fields as red

Question

For context, this is my form:

this.commentForm = this.fb.group(
    {
        commentId: [''],
        commentType: ['', ExistsWithinList(this.commentTypes)],
        commodity: ['', ExistsWithinList(this.commodities)],
        title: ['', Validators.required],
        description: ['', Validators.required],
        dealerId: ['', Validators.required],
        operator: ['', Validators.required]
    },
    {
        updateOn: 'submit'
    }
);

   

Template:

<form [formGroup]="commentForm" (ngSubmit)="submitForm()">
    <div class="row">
        <div class="col-lg-6">
            <label for="title">Title</label>
            <input type="text" id="title" class="form-control" formControlName="title" />
        </div>
    </div>
    <br />
    <div class="row">
        <div class="col-sm-3">
            <label for="commentType">Issue Type</label>
            <select class="form-control" id="commentType" formControlName="commentType">
                <option value="">--Select Type--</option>
                <option *ngFor="let commentType of commentTypes">{{ commentType }}</option>
            </select>
        </div>
        <div class="col-sm-3">
            <label for="commodity">Commodity</label>
            <select class="form-control" id="commodity" formControlName="commodity">
                <option value="">--Select Commodity--</option>
                <option *ngFor="let commodity of commodities">{{ commodity }}</option>
            </select>
        </div>
    </div>
    <br />
    <div class="row">
        <div class="col-sm-12">
            <label for="description">Description</label>
            <textarea rows="10" class="form-control" formControlName="description" id="description">
            </textarea>
        </div>
    </div>
    <br />
    <div class="row">
        <div class="col-sm-2">
            <span *ngIf="dealerCommentCreation; else updateSubmitButtonBlock">
                <input type="submit" class="btn btn-primary" value="Report" />
            </span>
            <ng-template #updateSubmitButtonBlock>
                <input type="submit" class="btn btn-primary" value="Update" />
            </ng-template>
        </div>
    </div>
</form>

When I focus on any of these fields, and then blur a field, all of the fields with 'Validators.required' highlight red (although, in the past, with newer versions of Angular, only one field highlights red)

Unfortunately I can't display the actual page (due to an NDA).

A snippet of relevant Angular dependencies (in package.json):

  "@angular/common": "4.4.6",
  "@angular/compiler": "4.4.6",
  "@angular/core": "4.4.6",
  "@angular/forms": "4.4.6",
  "@angular/http": "4.4.6",
  "@angular/platform-browser": "4.4.6",
  "@angular/platform-browser-dynamic": "4.4.6",
  "@angular/router": "4.4.6",

Answer 1

UPDATE -- So, after further investigation, I came to the realize that Angular 4's Reactive Forms had not yet supported the 'updateOn' property (That was a feature that became available with Angular 5+)

There are likely other ways to update your form's validation status (with Angular 4), but due to time constraints I migrated over to a Template-based solution -- most of the forms already established in this application are Template-based, and keeping our forms consistent gave me more reason to make the switch.

I will say, however, that I prefer Reactive forms, as they've made custom / asynchronous validation much cleaner (& seamless).