The igxList loading template does not show if I have static list items

[kdinev]

Description

I mark the IgxList as [loading]="true", but the loading template is not shown.

• igniteui-angular version: 7.1.1
• browser: N/A

Steps to reproduce

1. Create an IgxList with a loading template and a static header item

<igx-list [isLoading]="loading">
  <ng-template igxDataLoading>
    <div class="center-message"><span>Loading teams...</span></div>
  </ng-template>
  <igx-list-item [isHeader]="true">Teams</igx-list-item>
  <igx-list-item *ngFor="let team of teams">
     ...
  </igx-list-item>
</igx-list>

2. Declare a dummy data service with delay

  public get teams() {
    if (!this._teams) {
      this.loadingTeams.next(true);
      this._teams = new ReplaySubject<Team []>(1);
      this.getTeams().pipe(delay(5000)).subscribe(
        teams => {
          this._teams.next(teams);
          this.loadingTeams.next(false);
        },
        error => {
          this._teams = null;
          this.emitError(error);
        }
      );
    }

    return this._teams.asObservable();
  }

and

  ngOnInit() {
    this.apiManager.loadingTeams.subscribe(loading => this.loading = loading);
    this.apiManager.teams.subscribe(data => {
      this.teams = data;
    });
  }

3. Execute to see the result

Result

The header item is shown, but the data loading message isn't.

Expected result

The data loading message to be shown underneath the header item.