craftbukkit/nms-patches/net/minecraft/world/level/MobSpawnerAbstract.patch

--- a/net/minecraft/world/level/MobSpawnerAbstract.java
+++ b/net/minecraft/world/level/MobSpawnerAbstract.java
@@ -47,6 +47,7 @@
 
     public void setEntityId(EntityTypes<?> entitytypes) {
         this.nextSpawnData.getEntityToSpawn().putString("id", IRegistry.ENTITY_TYPE.getKey(entitytypes).toString());
+        this.spawnPotentials = SimpleWeightedRandomList.empty(); // CraftBukkit - SPIGOT-3496, MC-92282
     }
 
     private boolean isNearPlayer(World world, BlockPosition blockposition) {
@@ -148,7 +149,7 @@
                             }
                         }
 
-                        if (!worldserver.tryAddFreshEntityWithPassengers(entity)) {
+                        if (!worldserver.tryAddFreshEntityWithPassengers(entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER)) { // CraftBukkit
                             this.delay(worldserver, blockposition);
                             return;
                         }