That’s not a Brave specific issue; I’ve seen it frequently on Chrome (desktop) and on Safari (mobile). In particular, I’ve observed it when attempting to post a comment; usually when that happens I need to copy out my comment content, reload the page, paste the content back in and hit the Reply button again.

I don’t know for certain, but I’m guessing the cause has something to do with the Lemmy servers being overtaxed due to “Rexxit” related increased user activity. Of course, if that guess is correct, I’m afraid we can only anticipate the problem getting worse over the next several days.