Color difference between PAL and NTSC via RGB

Decided to finally get to the bottom of this: on my old crt TV I noticed that the reds are much more intense when switching to NTSC from PAL despite using an RGB connection. I’ve now observed this on my new TV as well when connecting my PS2. I couldn’t see the same when using a VGA-RGB connection and feeding signals from 50-60 hz to this TV, but it does happen on my other PC- RGB Scart setups with the other TV.

When connecting the PS2 to my Sony EDTV LCD, the colors stay also consistent. I use the same cables for the same hardware of course, so what are possible explanations for this?