With the new just-out-of-beta review system, after reviewing a post, you are immediately presented with a new post to review.
The Suggested Edits review queue requires minimum 2k reputation to review in general, but you're always allowed to review your own posts, regardless of reputation. In this case, your suggested edit approval was successfully submitted, but you didn't have enough reputation to continue reviewing.
You're right though; the
You need at least 2k reputation to review Suggested Edits message is confusing here. To handle cases like this, we have changed this message to
Thank you for your review. You need at least 2k reputation to continue reviewing Suggested Edits.