There's is some problem.. I'm on Linux with slow connection atm.
I wonder media doesn't stream until downloaded.
Earlier today, I had the audio work ok but I haven't seen the video on safe://cheburashka.movie
The audio at safe://cheburashka.movie just now, gives error in the dev tools console as:
Failed to load resource: net::ERR_CONTENT_LENGTH_MISMATCH
My connection is rather busy atm with something else; so, it's possibly that the file hasn't fully downloaded, though that's at odds with user expecting it just to stream what is available.
safe://zietemduun.draw worked.. after a short delay
.. though that was at a time I went into dev tools to look at the code - expect that didn't affect it.
However, doing a hard refresh now, I get the same problem there too.
The video code on both obviously looks good for what works normally.
Also, I notice that the Launcher has whiteout.. and remains so even with beaker closed now.. I don't know if launcher persists to download requests even if the browser is closed.