I've come across the sentence
父は休みの日はずっとテレビを見ている。(My father spends his days off watching television all the time.)
where it doubles in using the は particle. From another post, it seems that this would be a valid sentence if one of the particles marks the topic, while the other marks a constrast. Yet in this case, it seems that both particles mark the topic as I don't believe there is anything obvious to contrast. Would I happen to be missing something here?