I just embedded both the sharable link and iframe from YouTube and it saved and embedded fine. I don’t think it’s an extension conflict as I have all extensions enabled on my test site. It’s possible though, especially if you have an older version of one.
That being said, the update did include some minor changes to video embeds so there’s something going on.
Most likely it’s something unique with your setup. I haven’t had anyone else bring this up so it’s likely not a widespread issue.
I can probably best help if you send a message here: https://wpcoursesplugin.com/contact/
A video screen capture of exactly what’s happening would be super helpful.