Spawner items do not work

spawner items do not work in 1.21.3 Paper, 5.8.0 Dev, Crucible Latest version. I've been using this example from your wiki:

TestSpawner:
  Material: SPAWNER
  Display: 'Testing Spawner'
  Options:
    Placeable: true
  Spawner:
    Delay: 0
    MinSpawnDelay: 20
    MaxSpawnDelay: 80
    RequiredPlayerRange: 16
    SpawnCount: 4
    SpawnRange: 8
    MaxNearbyEntities: 8
    Mobs:
    - Type: ZOMBIE_SKILLED
      Weight: 5
      MinBlockLight: 10
      MaxBlockLight: 10
      MinSkyLight: 10
      MaxSkyLight: 10