HG spawn in Rathe Mountains should work the same way the cylopses do
 

In Rathe Mountains hill giants did not ever spawn in predictable static positions. They worked the same way cyclopses in rathe work; there are a bunch of trash wandering PH's some of whom will sometimes respawn as a cyclopse. So sometimes you can find a whole field full of cyclopse and sometimes there aren't any up.

I'm just confused why the HG spawns don't work this way, considering they are in the same zone and almost everyone seems to remember them working this way.

Prolly didn't know when they first put them in and then it just got put on the back burner. it's unfortunate in that it's not classic, but it's also unfortunate in that it takes some of the mystery out of getting certain rares to spawn as you know 100% that the HG spawns are not linked with a rare.

i thought everything was a ph for a giant even lizards and basilisks

That is how I remember it always working as well. People weren't ever solo-camping single specific locs at the HG hill.

Currently on green, the cyclopse spawns *do* work that way, it's a similar scenario. Big central hill will trash mobs roaming all over it, and seemingly almost any of them can potentially respawn as a cyclopse. It's not "cyclopse spawns at this loc every 7 minutes" which is how HG's seem to be functioning.