Remember two things - what goes North must go South - - and the Earth rotates.
If the ISS goes above the North Pole, it must come back ''down'' over the south Pole. (It makes an orbit, right?)
Now... while it is *doing* that, the Earth rotates.
So -today- you may see the ISS come from the South and travel to the North. But some days from now, thanks to the Earth rotating, and the ISS continuing to orbit (several orbits later), you may see the ISS start from the North and head South.
In a period of a few hours, our astronomy club once viewed two passages of the ISS - one to our East, the other to our far West. (Both were South to North that night). The Earth had rotated during those hours, and the ISS orbited. Someone placed properly (in China, perhaps) would have seen two passages as well - but both would have been North to South.