If there are new capabilities of 2.1.x or the imminent 2.2, you can try to workaround the problem by separating your update() function into separate callbacks for the different widgets in case there is some race condition that is causing the unexpected behavior when they all go through the same function.
Ultimately, it is probably worthwhile to submit a GitHub issue with your example and a reference to this topic so that it can be fixed in a future minor or micro release.