I'm in chapter 2, playing Iorveth's side.

Right after calming the mob when Stennis was blamed for poisoning Saskia, I went to talk to Philipa about going to the Kaedweni camp through the mist, and when I got to the mist, it just did not appear(No 'Special mist screen'), I just found myself on the Kaedweni side with no NPC around.

Has anyone encountered such a problem?

Try updating your video card drivers.

And make sure you aren't forcing anything via your graphics card driver, it should be set to "Application Controlled".

I don't think it has anything to do with my video card, I already had 1 playthrough (Roache's side) and the mist did trigger.

This time, nothing happens...

You aren't going to know unless you check.

Anyway, it's your game.

Sorry I didn't mention it, but I did just update my driver, and it didn't help.

Thanks anyway.