How does the defender AI work for dual-CM Pokemon in gyms?

https://pokemongo.gamepress.gg/trainer-battle-update-analysis

I gave my hundo Blissey dazzling gleam/psychic and stuck it in a gym for my niece to battle. I thought it would be more formidable but while it would use both charge moves it seems that it alternated them in both charging/using rather than being able to spam them together.

Blissey is still just a bump in the road post nerf. A vaporeon can take it down just about as fast as a metagross without dodging. Sad to see her go