sterretje:
as far as I can recall, 24Mhz still exhibits the behaviour.
When you get a chance, give it a try just to be sure. I'm fairly certain we have the same logic analyzer. You'll see them with different stickers but I think they all have the same hardware and firmware inside, copied from the Saleae Logic 8. I get the same output as in the picture you posted at 16 MHz.