OK I have had a play around with this and I don't really see what is broken.
Two things, firstly the overlay that is generated by Hearthstone Deck Tracker is not picked up in either a Game Capture or a Window capture in either 0.13.4, 0.14.1 or OBS Classic so as far as I can see this never worked in a straight forward way -
@CapnCrunch is that your understanding or do you have it working in a particular version? If you have it working please share details of all the sources in your scene where it works and which version.