Bug in 708 CC generation - background transparency

Hi - I've brought this up to an Adobe tech service rep who said he'd push this to the devs and I haven't heard anything so I'm posting it publicly:

Using the new transcriber to CC generation workflow is great; I like it a lot. However, when they're generated, the background behind the captions are translucent and as a broadcaster they should be opaque by default. If it could be fixed where it's opaque by default OR a user able to change it in preferences I'd be very grateful.