Mob spawners do not spawn any monsters in 1.9 Pre-Release 2. The same map in Pre-Release 1 spawns mobs. I have uploaded a demo superflat world along with screenshots of the same map running in both Pre-Release 1 and 2 respectively.
MC-97665
Mob Spawners do not spawn Mobs
Resolved
Duplicate
1
Skylar Ostler
(Unassigned)
Unconfirmed
Minecraft 1.9 Pre-Release 2
Retrieved
Duplicate of MC-97491.