I believe Spellcraft and other effects vs spells are not working on cloud spells. I noticed this on a different character some time ago and recently on my current who has spellcraft. This is likely due to how the save is generated but if it could be fixed that would be nice. If it's intended then sorry!
Cloud spells count as poison rather than spells oddly enough.
Their save is often poison, yes, but they should still count as spells if it can be fixed.
It's a NWN bug. Some spells don't add spellcraft to the save.
Not sure they can be counted as both at the same time. Could be mistaken!