Again forgive me if I dupped this I saw this issue for the console editions an such..

Okay so I have been noticing that mine, versus my friends, is not spawning nearly as many mobs as hers. we are the same 1.9 pre release 2 etc etc normal difficulty and such. Even mine on hard spawns hardly any.

Even my cave spider spawner makes that flash animation like it spawned some but nothing appears like it's on peaceful or something and it's not. I have been standing next to it for 10 minutes and nothing. My cave spider spawner was working great up until I started lighting all of the cave around it. I will add more when I can!