Strange, but it indeed does happen, even in 2.8. Perhaps a lack of spawn nodes?
Also, queens can spawn in closed-off space in citizens vs monsters and be blocked.
That's unlikely; I checked all the maps and barring the starting blocks, all of them have at least one large unit spawn.
What I meant is that I think the Queens are spawned last? Does the order in the .rul files determine spawn order? And if all the spots are taken by small spiders, what's their momma going to do?