Hi Langdon,
Mushrooms definitely are fickle, from my understanding of the fungi life cycle I have a theory as to what happened there.
The mycelium in the primary bed has a ton of food, that sounds like a massive substrate

When you grow mushrooms indoors in jars you wait until the mycelium has fully colonized the sealed substrate and then wait an extra week before you pop it out of the jar and into the humid fruiting area. In indoor cultivation this is primarily to limit competition from other airborne microbial contaminants colonizing the substrate but I believe it is also part of the simulation of the fungi life cycle.
So what I am saying is that the mycelium will only activate the fruiting of the mushrooms when it is out of food in its current environment. So they are doing fine I think just too busy eating to make mushrooms, they will do that after more of the cellulose and lignin in the pile has been consumed.
The ones that fruited likely did so because you removed them from the food source, they started to die or at least realize and say "like hey where'd the food go?" So in this environment in order to survive the mycelium induced sporulation.
Anyhow that is my take I hope it helped a little bit and it's entirely possible I am wrong just my own little theory
Daniel