Don’t know if this counts as a bug, but embedded YouTubes no longer display a thumbnail in firefox.
Testing another one…
Confirmed, this is a new regression. @techAPJ can you have a look today?
Looks like Firefox does not support protocol-relative URLs (
//img.youtube.com) in CSS anymore? To fix this I switched to using
https://img.youtube.com URL by default as per this answer on Stack Overflow.
Thanks for reporting this issue @smrtey