I submitted a suggested edit, and when I checked the status later, I saw a message saying "This item is no longer reviewable", with no record of any reviews.
I searched meta for an answer, and found this: What can cause "This item is no longer reviewable"? However, the answer there doesn't seem to explain this. According to the answer, what happened in that case was that the edit suggestion was made to a previously edited post, and while the new suggestion was in the review queue, the revision it was based on was rolled back, invalidating the suggestion.
However, the post I edited, Lucene.net - How do I extract small snippets of texts from each match?, had no previous edits when I started editing, and as of this writing still hasn't been edited. I guessed that maybe an edit was made while I was editing, and was rolled back immediately, before there was even enough time for me to get the warning at the top that the post had been edited since I began. However, if that were the case, there should be a link to the edit history at the bottom of the post. Here's how it looks right now - note that the the area where that link should be, indicated by the FHRC, is blank:
Furthermore, I am not able to resubmit my edit. Figuring that regardless of what caused it to be designated "no longer reviewable", the edit is highly desirable (there was no language tag) and the post is still in its original state, so I resubmitted. Unfortunately, instead of being submitted as a new edit suggestion, it was treated as a modification to my original suggestion, which remains "no longer reviewable". There are no new suggestions in my activity log, and when I look at my original suggestion, I see that it has been modified to reflect a small difference in the resubmitted edit:
This is rather odd, since I've revised edit suggestions that were still under review before (the same way - by clicking the edit link in the post), and it always lets me edit starting from where I left off, but now if I edit, I start from the original post rather than from my my not yet approved edited version. Yes, when I view the post, I see the original, not an edited version that's viewable only to me until it's reviewed, as normally seen when one has an edit suggestion under review. But if that explains why I'm starting from the original version when I click edit, shouldn't it follow that this would be a new edit suggestion rather than a modification to the previous one?
Update 8/16/2013: Based on the feedback, I'm adding the bug tag. The bug to fix is that if an edit for some reason becomes unreviewable, subsequent edits from the same user should either be treated as new edit suggestions rather than modifying the original suggestion, or they should make the suggestion reviewable again.
Case in point, I still can't suggest an edit on that post, and the language tag still hasn't been added. I was going to ask if someone else could take care of that, but by this point it would be better to just wait until tomorrow and see if I can make the edit myself - it'll be interesting to see if my unreviewable edit suggestion will prevent me from editing the post after I cross 2,000 rep.