work for #8530

src/survey.ts

@@ -3330,7 +3330,9 @@ export class SurveyModel extends SurveyElementCore
   }
   private updateActivePage(): void {
     const newPage = this.isShowStartingPage ? this.startedPage : this.currentPage;
-    this.setPropertyValue("activePage", newPage);
+    if (newPage !== this.activePage) {
+      this.setPropertyValue("activePage", newPage);
+    }
   }
   private onStateAndCurrentPageChanged(): void {
     this.updateActivePage();
@@ -6073,11 +6075,11 @@ export class SurveyModel extends SurveyElementCore
           isCompleted: string,
           response: any
         ) {
-          self.isLoading = false;
           if (success) {
             self.isCompletedBefore = isCompleted == "completed";
             self.loadSurveyFromServiceJson(json);
           }
+          self.isLoading = false;
         }
       );
     } else {
@@ -6086,10 +6088,10 @@ export class SurveyModel extends SurveyElementCore
         result: string,
         response: any
       ) {
-        self.isLoading = false;
         if (success) {
           self.loadSurveyFromServiceJson(result);
         }
+        self.isLoading = false;
       });
     }
   }

tests/surveytests.ts

@@ -6587,6 +6587,49 @@ QUnit.test("surveyId + clientId", function (assert) {
   assert.equal(q1.name, "q1", "The survey created from the string");
 });
 
+QUnit.test("surveyId + clientId several page render", function (assert) {
+  let log = "";
+  let curState = "";
+  const json = { questions: [{ type: "text", name: "q1" }] };
+  class dxSurveyServiceTester extends dxSurveyService {
+    public getSurveyJsonAndIsCompleted(surveyId: string, clientId: string, onLoad: (success: boolean, surveyJson: any, result: string, response: any) => void) {
+      if (onLoad) {
+        onLoad(true, json, clientId, "");
+      }
+    }
+  }
+  class SurveyTester extends SurveyModel {
+    protected createSurveyService(): dxSurveyService {
+      return new dxSurveyServiceTester();
+    }
+    protected propertyValueChanged(name: string, oldValue: any, newValue: any, arrayChanges?: ArrayChanges, target?: Base): void {
+      super.propertyValueChanged(name, oldValue, newValue, arrayChanges);
+      if (name === "isLoading" || name === "state" || name === "activePage") {
+        log += ("-> " + name + ":" + newValue);
+      }
+    }
+    protected onLoadSurveyFromService(): void {
+      super.onLoadSurveyFromService();
+      curState = this.state;
+      assert.equal(curState, "loading");
+    }
+    protected setPropertyValueDirectly(name: string, val: any): void {
+      if (name === "activePage" && !!val) {
+        assert.ok(this.activePage === undefined, "this.activePage undefined");
+        assert.ok(!!val, "new activePage");
+      }
+      super.setPropertyValueDirectly(name, val);
+    }
+  }
+
+  let survey = new SurveyTester({ surveyId: "surveyDummyId", clientId: "completed" });
+  assert.equal(survey.state, "completedbefore", "The survey is running");
+  assert.equal(log, "-> state:empty-> state:loading-> isLoading:true-> activePage:page1-> state:completedbefore-> isLoading:false");
+
+  let q1 = survey.getQuestionByName("q1");
+  assert.equal(q1.name, "q1", "The survey created from the string");
+});
+
 QUnit.test(
   "Question description and text processing, variable, Bug #632",
   function (assert) {