I don't know. I have noticed that as well. I hope someone can fix it. It really deters from the use of this website. The same thing happened to fishtanktv.com and that site is full of absolute spam trash now. Even when you post something you get spam as a reply.
Most if not all of the mods are North American based, and I don't think any are night owls. Come morning one will grab a cup of coffee & fix it, pretty much SOP for many forums. Problem with forums being overrun with spam is mods not doing just that, it isn't that tough of a thing.