Assignment lingers on "moved" topic

Two weeks ago I assigned a topic to a group.

Last week I realized it was the same subject as a different, older thread that was already assigned to the same group.

So I “moved” the posts in the newer topic into the older topic.

The move-source topic stayed assigned. So someone from the group responded when the fix had been deployed. The OP responded with a “thank you” and marked the solution. And IMO none of that should have happened.

IMO the assignment should have gone away. In fact, IMO Select all -> Move should result in closing (and therefore unassigning) the thread. I shouldn’t have further cleanup to do on a post that should be empty because its contents were “moved” to another thread.