Title. The language of a post or comment is never displayed, nor can it be defined when writing posts or comments.
This leads to posts/comments with the language set to “undetermined” which leads to them appearing to users that didn’t select the actual language.

Edit: Additionally some communities seem to have started disallowing “undetermined” as a post/comment language, leading to Jerboa users being unable to post/comment. I’ve encountered !foodporn@lemmy.world so far.