PrimeNG File Upload Progress does not update when using custom uploadHandler

I am trying to use the PrimeNG File Upload Component

But I am uploading to an API so I am using a custom uploadHandler like so:

<p-fileUpload #fileUpload name="fileUpload" 
              (uploadHandler)="uploadHandler($event)" customUpload="true" fileLimit="5"
              multiple="multiple" accept="image/*" maxFileSize="1000000">

With a component.ts that invokes the following:

uploadedFiles: any[] = [];
@ViewChild('fileUpload') fileUpload: any;

constructor(private wpService: WordPressService, private cd: ChangeDetectorRef) {}

async uploadHandler(event) {
    this.fileUpload.disable = false;
    this.fileUpload.progress = 5;
    this.fileUpload.onProgress.emit({progress: this.fileUpload.progress});;
    this.uploadedFiles = [];

    const perFilePercent = 95 / event.files.length;
    this.fileUpload.disable = true;
    for (const f of event.files) {
        await this.wpService.uploadFile(f).then(response  => {
            const thisFile = f;
            thisFile.url = response.source_url;
            this.fileUpload.progress += perFilePercent;
            this.fileUpload.onProgress.emit({progress: this.fileUpload.progress});

    this.fileUpload.files = [];;

The issue is that even though I am trying to force the progress to change manually by doing this.fileUpload.progress += perFilePercent; AND this.fileUpload.onProgress.emit({progress: this.fileUpload.progress});, nothing happens.

The curious bit is that if I then bind a progress bar component to the value of this.fileUpload.progress, it will update.
For Example:

<p-progressBar [value]="fileUpload.progress" [showValue]="false"></p-progressBar>

Causes the behaviour to work as expected, while the progress bar inside the the actual file upload component stalls and does not update past the very first invocation.

A video of this behaviour:

I feel like I am doing something wrong in the lines that set the viewchild values or the event emitter but I cannot figure out what is wrong nor what I should be doing.

Source: Angular Questions