fix(combo): ensure synced bindings on check

Author: ddaribo

projects/igniteui-angular/combo/src/combo/combo-item.component.ts

@@ -66,15 +66,17 @@ export class IgxComboItemComponent extends IgxDropDownItemComponent {
      * @hidden
      * @internal
      */
-    public get disableTransitions() {
-        return this.comboAPI.disableTransitions;
+    public override ngDoCheck(): void {
+        // Sync state from services once per CD cycle so template bindings return stable field values
+        this._selected = !this.isHeader && this.value != null && this.comboAPI.is_item_selected(this.itemID);
+        this._disableTransitions = this.comboAPI.disableTransitions;
     }
 
     /**
      * @hidden
      */
     public override get selected(): boolean {
-        return this.comboAPI.is_item_selected(this.itemID);
+        return this._selected;
     }
 
     public override set selected(value: boolean) {
@@ -84,6 +86,16 @@ export class IgxComboItemComponent extends IgxDropDownItemComponent {
         this._selected = value;
     }
 
+    /**
+     * @hidden
+     * @internal
+     */
+    public get disableTransitions() {
+        return this._disableTransitions;
+    }
+
+    private _disableTransitions = false;
+
     /**
      * @hidden
      */