I had the issue a few minutes ago, when replying to a new post (original post was from Kbin instance). I added two languages on Lemmy’s settings (because I’m bilingual) and the error was still appearing.

The workaround was to go directly into Lemmy and make the comment from there, selecting the language from the drop-down option. It would be great if Voyager would let us set a default value for comments or better yet, the toggle within the comment.

Edit: this comment worked as expected, so maybe it’s an issue with posts outside Lemmy.world?