Media in Twitter streams are broken

Firefox Nightly
#1

Hello, Community!

I’ve noticed over the past weeks that Nightly is unable to display some video and other imagery in my Twitter stream, e.g.:

https://twitter.com/politicomx/status/877179271357149184

Instead, I see the image area change to black with messaging like “Could not play media.” I’ve also just discovered that the two examples I’d isolated now do play, with no other change – Nightly hasn’t been updated or closed. So that makes it seem there is some intermittent character to this.

Facts: Twitter; Nightly current; new MBP with macOS 10.12.5; current Flash installed and enabled.

#2

i’ve been encountering this on some builds as well.
Dont know if its a true bug or connection problem situation

#3

I wonder if it’s something to do with HTTPS-only for Flash. Truthfully I don’t know enough about what Twitter does for embedded media. I don’t even know how to get the source URL for embedded bits like video.