Trial spawner cannot be activated in peaceful difficulty

Trial spawner cannot be activated in peaceful mode, even if a passive mob spawn egg is used on it. When switching from another difficulty to peaceful, the spawner instantly deactivates.

This behaviour is different from normal spawners, in which passive mobs can spawn from a spawner regardless of difficulty (as long as the spawning conditions are satisfied). 

I am not sure if this is intentional or is just a bug.