Hmm . . I just did some research out of curiosity, and apparently we're both right, as some describe it one way and others another.
It's also a very common issue, and from what I'm reading it's caused by poor oil circulation at the top of the engine and vanos area. To fix it permanently, you can take it to a dealer and they'll install what's called an oil accumulator to ensure that there is enough oil on top. But most people just add a little extra oil to get rid of the noise.