It did. Luckily the power was off, but the milk had ran through the cooling slits and flooded over the motherboard and worked its way into the various fans and other bits of HW I had jammed into it, which was quite a lot at the time.
I completely dismantled it, washed the mobo in distilled water and dried it over a week before testing it.
I had to replace the fans of course, they developed quite a noise and yoghurt aroma...