RxJS5 finalize operator not called

Are you sure one of combined Observables actually completes? With either .complete or .error?

If none of the combined Observables completes, finally will never be called.

In observables, firing and completing are not the same thing.

Even though each of the items emits a value, route.queryParams by definition will never complete since that is how Angular implements it, as a non terminating observable. You will need to manually complete it for your finalize to execute since combineLatest will only complete when EVERY observable being combined inside of it has completed.

combineLatest(
  this.route.queryParams.pipe(take(1)), // take(1) will complete the observable after it has emitted one value
  this.myService.callDummy1(),
  this.myService.callDummy2()
)
.pipe(finalize(() => console.log('Does not work!')))
.subscribe(results => ...);

This will complete.