This comes as no surprise ..

I have received my downgrade to Silver letter and "new" card, despite having collected the requisite 1500 TP in the year ended 8th Dec 2013.

If the IT system cannot cope with AA flight postings, correct TP status recognition and so on, I'm not at all puzzled by the randomness of such emails.

Perhaps the peculiar email timing also applies to the internal relaying of comments posted via ba.com, and explains the frequent latency in responses.