During a game as the unfallen the Ai drained the hero market before I had a chance to get any, generally don't set buying the ships/heroes as a priority but I found myself needing a few extra heroes then got blocked from purchasing them due to a quest. maybe its just me but I'm curious as to whether anyone else has noticed this.

I always though it was a mechanic reserved for players, since there was only ever one hero in it when I unlocked the tech. Now I'm bugged I couldn't make better use of the Vodyani hero bonuses!

I have that impression two. I'm able to get abotu 3 heroes by turn 60 and very rarely I'm not able to get a hero from market for the rest of the game.

Don't know how it works though.