Angular 6, this.formGroup.updateValueAndValidity() not working properly

updateValueAndValidity() is bottom-up, so if you call this method over a control, it will check only validations of this control and their parents, but not their children.

For more details, see AbstractControl#updateValueAndValidity on github to how it works.

  updateValueAndValidity(opts: {onlySelf?: boolean, emitEvent?: boolean} = {}): void {

    if (this.enabled) {
      (this as{errors: ValidationErrors | null}).errors = this._runValidator();
      (this as{status: string}).status = this._calculateStatus();

      if (this.status === VALID || this.status === PENDING) {

    if (opts.emitEvent !== false) {
      (this.valueChanges as EventEmitter<any>).emit(this.value);
      (this.statusChanges as EventEmitter<string>).emit(this.status);

    if (this._parent && !opts.onlySelf) {

I stumbled upon this last week too, and I came to the conclusion that this is the expected behavior. The docs states the following:

By default, it also updates the value and validity of its ancestors.

Note that it says "ancestor" and not "descendants". This means that when you have run updateValueAndValidity() on control1 and control2, and they're both valid, myForm will be marked as valid too.