<ion-select> not changed when data binding is changed

In my setting page, the user can select language. When language changed, the text in setting page should be changed accordingly. It works fine for <ion-label>, but <ion-select> is not changed until user clicks it.

How can I make the content of <ion-select> change once language is changed?


    <ion-list>
        <ion-item>
            <!-- this works well -->
            <ion-label>{{ "pages.settings.items.language" | translate }}</ion-label>
            <ion-select [(ngModel)]="lang" (ionChange)="updateLang()">
                <ion-option value="zh">中文</ion-option>
                <ion-option value="en">English</ion-option>
                <ion-option value="fr">Français</ion-option>
            </ion-select>
        </ion-item>
        <ion-item>
            <ion-label>{{ "pages.settings.items.firstDayOfWeek" | translate }}</ion-label>
            <ion-select [(ngModel)]="firstDay" (ionChange)="updateFirstDay()">
                <ion-option value="0">
                    <!-- this doesn't work -->
                    {{ "pages.settings.items.sunday" | translate }}
                </ion-option>
                <ion-option value="1">
                    <!-- this doesn't work -->
                    {{ "pages.settings.items.monday" | translate }}
                </ion-option>
            </ion-select>
        </ion-item>
        <ion-item (click)="openBackup()">
            <!-- this works well -->
            <ion-label>{{ "pages.settings.items.backupsAndRestore" | translate }}</ion-label>
        </ion-item>
    </ion-list>
    updateLang() {
        if (this.lang !== this.config.lang) {
            this.translate.use(this.lang);
        }
    }

@mhartington Could this be a bug?