This question was migrated from a different site, then closed as a duplicate. Later on, it was locked for historical significance. The revision history shows it correctly, and the vote arrows and flag option is gone (as expected). However, the lock notice for historical significance doesn't show up. Instead, the "rejected migration" notice shows up, which makes no sense, since closing as duplicate does not reject the migration, and even if it did, the date should be the same as the date of the closure. Instead, the date on the "rejected migration" notice is the same as the (later) date the lock was applied.
It may be that the lock is what triggers the "rejected" notice, and also causes the system to ignore any other lock notice that may have been applied.
Update: The status-completed tag was applied, but there are a number of questions on Server Fault still exhibiting this bug. The same query can be done on other sites to find such questions, excluding unanswered ones (which would also include merge stubs). If, per the answer, the resolution is to not fix this notice, the question should be tagged status-declined instead.