I searched around but couldn't find this, apologies if it has been asked. For as long as I can remember, podcasts in my subscription list will randomly get an exclamation mark next to them and stop updating. I've lost count of how many times this has happened. This week, it's Diggnation (MP3) and Galactica Watercooler. The only way I can fix it is to delete the podcasts and resubscribe. This is really annoying. Does anyone know why this happens?