How do you get Valken's coup instead of Iosef's?

I've done a few playthroughs now, and whenever I end up getting couped, it's always Iosef. At this point I'm starting to think I'm doing something without realizing it because I just can't seem to get Valken's version.

If anyone knows what actually determines who leads the coup, or has a guide that worked for them, I'd really appreciate it. I'd like to see Valken's coup for myself instead of getting Iosef every single time.