Detached topic title after topic merge

Topic title is generally the same as the first post one; however, when a moderator merges two topics, the older one gets the title of the newer one and first post editing won't change the title anyway, like if topic title had got detached from first post one.

Example
Topic titled A has the first post A and the second post B differently titled; a moderator splits post B from topic A, then selects topic B for merge and chooses topic A. Now the topic is titled B despite the fact that the first topic is A.
If the moderator had selected topic A for merge instead of topic B, the issue wouldn't have raised.