Why is it OK to have multiple bosses spawned but not normal force spawn NMs?

[Armauk]

This is true. no matter how fast your machine is you can't out pop an average JP popper. The other night, I wasted almost an hour just trying to pop a Kharon against 4 JPs. I could only pop it after they left. This frustrated me to no end.

I feel your pain. It's especially bad when a seal NM drops a KI to spawn a bigger NM.