Heresy is a comedy talk show on BBC Radio 4, created and originally hosted by David Baddiel, now hosted by Victoria Coren Mitchell. In the show, the presenter and a panel of guests commit "heresy" by challenging people's most deeply received opinions on a subject, in front of a studio audience.
Heresy is a comedy talk show that was originally hosted by David Baddiel on BBC Radio 3 but is now hosted by Victoria Coren Mitchell on BBC Radio 4.
Context does not say whether or not Heresy was originally hosted on a different channel, simply that it is on (presently) BBC Radio 4. The system probably tripped on the semantics of the verb tenses.