Some of you may have noticed issues with any overlay not showing recently. This is caused by a bug with Hangouts which is currently being investigated. In the meantime you can use this workaround.
Start your Hangout using https://talkgadget.google.com/hangouts/_/ which will make the overlays including lower thirds work again.
As you can see below it works just fine. And yes, this is the material design version I am still working on.........if I have time, that is.