I'm having a similar CTD-problem on my PC, despite the game isn't in ironman-mode.
What I discovered, is that several of the diplomatic options the player has, are somehow not present in the cloud save. When using the auto-save; which is stored at my PC, since storing them at the cloud caused a CTD as well; I can continue playing without a problem.
@ Jamy30: Perhaps it's worth a try to check your diplomatic options when selecting your cloud-save and checking them again the moment the game is loaded?

I've added two screenshots, showing the problem with the missing diplomacy.
Thorin
