Inconsistent behavior of Javascript Click/Change events in the Customizer

I’m noticing a strange behavior in 4.4-b4 regarding the Change event triggered by clicks in widget buttons, in the customizer.

Here’s an animated Gif with a test widget in the current version (4.3.1), with the expected behavior:

https://dl.dropbox.com/s/mime1qqemk3a2c4/wp431.gif

And another Gif, showing the issue in version 4.4-b4:

https://dl.dropbox.com/s/xki1ye0op9mqsq8/wp44b4.gif

The clicks end up affecting another elements, with no apparent reason.

The JS code used in the test widget is very simple, here’s the Gist:

https://gist.github.com/4c9cc6c59831a47bc88b

The complete test widget plugin can be found here:

https://www.dropbox.com/s/elzg9qcgqlh93m8/simple-widget.zip?dl=0

Both WordPress installs are new, using the Twenty Twelve theme, with no other plugins running.