So, today i’ve edited this huge post here again:
And at some point all of embedded video links became just links, initially i thought:
But looks like it’s not the problem, here i’ve posted just one video and it still look like just link:
Is this Discourse bug? Is this just me seeing this?
I see other’s embedded video still, for example in What are you listening now? thread…
Test
https://www.youtube.com/watch?v=2Q_ZzBGPdqE
Hmmmm, !=good.
I see the two links.
Works fine here on xfce, in YT and vlc.
Edit: chromium here (for vaapi).
Me & @anon379864 are both on KDE (wonder if that could possibly be factor here?), i use Firefox as browser…
Nothing changed or updated since it’s started on my system, so i don’t think it could be DE / packages related anyhow
Tried to exclude client-side stuff which comes to mind:
Still don’t see embedded ones 
I’m out of ideas…
Wait, yt and VLC?
I’m not talking about youtube itself, i’m talking about embedded videos (meaning when you can see their preview inside forum and click to play without going outside of forum)
OK, this one from @Pudge was the first I found and it works fine.
Edit: just tried forum music thread and all is good.
My link above, which atm in EOS does not show the pic, is supposed to render like this:
That’s from cough cough another forum.
In contrast, my post up above, renders like this for me:
= no picture.
These two links, your “test” and @anon379864’s “Hmmmm, !=good” are actually direct YT links, so what to expect ?
I tried to explain it with my last post, by actually capturing a static screenshot to show others what i see here at my end… just to ensure that none of us misunderstands what the others are saying. So the nub of the issue is that atm, in the EOS forum, for whatever reason, links which DO fully render [pictorially] on other fora, are not rendering here for us with the image preview shown… all we see is the raw URL itself.
Have you seen my edited post above ? We have a music thread here and it’s looking good and vids working fine. So please point me to a thread where you can’t see vids or pictures.
THIS very thread, beginning with OP.
For example i still can see yesterdays AC/DC
OK, now I know what you both means.
Just posted a new link in the music thread and the picture don’t show up.
I think, that’s not on us.
Did you test the Enter before and after the link you put ?
Not sure what you mean…
Like:
?
If so - then yes, it’s still same 
Or if you mean Enter key - yes, no effect too
nope like this
…enter
link enter
ok so the problem is other…We will check this thanks…
there is a similar problem with the yt frontend https://invidio.us - video-links were displayed incorrectly (greyed out) and also not clickable (mime-type not supported). meanwhile they are presented as pure text-links, so a bit of a progress 