This is not an actual answer, but I just like to add more info to this issue.
I was searching for when this message shows up in case this was some generic message that shows under any circumstances. Here's what I found out (the conditions may be different for mods/10k+):
- This doesn't show on reviews of posts that aren't mine. Whether I was one of the reviewers or not, doesn't seem to matter.
- That exact message shows under 2 conditions (In both cases, I have to be the owner of the post):
- By itself; when I had reviewed an edit on own post (Ex: Like the on the Question).
- Accompanied by another message; when I have not participated in the edit review of my own post and that suggested edit is the last one on my post and the suggested edit has been approved. For example, I could see it on this suggested edit.
This suggested edit to your post has already been handled and your action is no longer required.
If you disagree with this edit being approved, you can return your post to its previous state using the Reject button below.
Once I edited that post myself (I removed an irrelevant tag), the second line disappeared and I can see the first line only as that suggested edit was no longer the last edit.
So it looks like it is some kind of Generic message, which is accompanied by other messages depending on available actions that we may do after the review is completed. But I don't know if there's any other case than the one shared in the screenshots above.