The idea is somewhat like emails. Should the subject of an email be repeated in an email?
I don't think an exact copy should occur, that is stylistically annoying, but I do think there should be some repetition of the concept.
Very often a person will write something in the title, then in the contents go in a completely different direction. What results is that some answer the title questions, and some answer various things in the body that are unrelated to the title. And it is still unclear what the OP really wants, the title question or the slightly different question in the body.
Also, as to UI design, the title is often separated from the body to such an extent (in size/weight/kind) that it is hardly read at all after the link from the main screen is read, so there is the problem of a discrepancy in understanding of the title and the body even when consistent.
For example, in the question:
Preferences or priorities
it was very unclear in reading the examples that the title had anything at all to do with the examples given, in fact it was easy to answer the problem in the example rather than trying to answer the title.