This seems to be a recent thing - questions migrated are now being shown as "closed off topic" and "migrated to ...".
This was before the change.
This is how it looks now
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So...when a question is migrated a few things happen:
These are all distinct things in the system, and unfortunately due to an optimization for migration performance, it made the "Locked Date" not persist correctly. The end result of that bug was a different code path for statuses being used and some duplication that you see in the screenshot above.
This is now fixed across the network, and we cleaned up the missing LockedDate entries for those posts, you should now (like before) see a clean migrate-only status box at the bottom.