Default values not shown in multi select

Hi,
I have a form on an Ionic4 app done with Form Builder.
In this form, I have a multi-select field: “favouriteSports”.

When I open the edit view of this form the field doesn’t show the selected values:

1

but if I click on the select I can see that the values are selected, they just don’t appear when the form is opened.

2

This is how I have defined the field in the form:

favouriteSports: [this.userProfile.favouriteSports || '',
Validators.compose([
  Validators.required,
])],
  
favouriteSports: [
{ type: 'required', message: 'This field is required.' }
],

This is the html:

			<!-- FAVOURITE SPORTS -->
	  <ion-item>
		<ion-label color="dark" position="stacked">{{ 'Favourite sports' | translate }}</ion-label>
		<ion-select multiple="true"
					formControlName="favouriteSports"
					cancelText="Cancel"
					okText="OK"
					class="ion-no-padding smalltext">
		  <ion-select-option text-wrap *ngFor="let item of eventSportOptions" [value]="item.name">{{item.value}}</ion-select-option>
		</ion-select>
	  </ion-item>
	  <div class="validation-errors">
		<ng-container *ngFor="let validation of validationMessages.favouriteSports">
		  <div class="error-message" 
                            *ngIf="profileForm.get('favouriteSports').hasError(validation.type) &&
                            (profileForm.get('favouriteSports').dirty || profileForm.get('favouriteSports').touched)">
			<ion-icon name="information-circle-outline"></ion-icon> {{ validation.message | translate }}
		  </div>
		</ng-container>
	  </div>

Why the chosen options are not shown if they are selected?
If I open and close the select without change anything, the values appear selected.

Thank you

Claudio

If I initialize the field in this way:

      favouriteSports: [['ciclismo', 'podismo'],
        Validators.compose([
          Validators.required,
        ])],

the result is the same.
1

It seems empty but if I open the select…
ScreenHunter_700 Mar. 12 10.39

and if I close it without change anything, it appears filled:
ScreenHunter_701 Mar. 12 10.40