Today a question was asked on Writing. Five users voted to close as off-topic, belongs on another site (English, a defined migration path for us). The question shows as on hold, off-topic with no migration link. Somebody asked about it on meta, so as a moderator I tried to see what had happened.
My first stop was the (moderator) timeline, which shows the five close votes, the post being locked, and then the post being unlocked. That's consistent with it having been migrated and then the other site closing the question; rejected migrations bounce back. I wanted to look at the question on the other site to confirm that (and see the close reason) -- and found no link, anywhere: not in the post revision history (for which I had to construct the URL by hand), not in the timeline, and (as a presumed bounce-back) no longer on the question itself.
I then looked for the question, first using search and then using "newest questions", and didn't find it. Did the other site not only close but delete the question in the last 8 hours? Maybe, but that didn't sound likely.
So I went back to the timeline, where I then noticed that the timestamps for the lock and unlock events are identical. That sounds like a failed migration, but the only reason I know of for that is the user being suspended or question-blocked on the target site. This user has no account on the other site, so it's not that. The only other thing I could think of was that maybe the IP address became blocked between the time the question was asked and when the migration was attempted -- but no, the IP isn't blocked.
What happened here? Did I miss something in the available tools that could have told me? If not, is there anything that can be improved in the tools that would have made this easier to figure out?