Hello, I made the setting in 3.3.5 same result.
Cannot display a youtube video on old posts.
Installing the 1média Embed extension and removing the youtube BBcode does not provide any solution other than for new posts.
Currently I have two display version of youtube videos:
https://forum.dnepr-ural.fr/viewtopic.php?t=1948 displays nothing
https://forum.dnepr-ural.fr/viewtopic.php?t=1977 poster [youtube] nnLmzQ6TGjs [/ youtube]
And this since the version change since 3.1.9
to 3.3.5