src/app/subsystem-list/subsystem-list.component.spec.ts

@@ -84,7 +84,7 @@ describe('SubsystemListComponent', () => {
     fixture = TestBed.createComponent(SubsystemListComponent);
     component = fixture.componentInstance;
     fixture.detectChanges();
-    expect(TestBed.get(Router).navigateByUrl).toHaveBeenCalledWith('/DEFINST');
+    expect(TestBed.get(Router).navigateByUrl).toHaveBeenCalledWith('/DEFINST', Object({ replaceUrl: true }));
   });
 
   it('should detect when instance is not selected', () => {

src/app/subsystem-list/subsystem-list.component.ts

@@ -109,7 +109,7 @@ export class SubsystemListComponent implements OnInit, AfterViewInit, OnDestroy
 
       // Redirect to default instance if instance is empty or invalid
       if (!this.subsystemsService.getInstances().includes(params.instance)) {
-        this.router.navigateByUrl('/' + this.subsystemsService.getDefaultInstance());
+        this.router.navigateByUrl('/' + this.subsystemsService.getDefaultInstance(), { replaceUrl: true });
         return;
       }