Paper/paper-server/patches/sources/net/minecraft/world/effect/MobEffectInstance.java.patch

--- a/net/minecraft/world/effect/MobEffectInstance.java
+++ b/net/minecraft/world/effect/MobEffectInstance.java
@@ -216,6 +_,7 @@
             int i = this.isInfiniteDuration() ? entity.tickCount : this.duration;
             if (entity.level() instanceof ServerLevel serverLevel
                 && this.effect.value().shouldApplyEffectTickThisTick(i, this.amplifier)
+                && new io.papermc.paper.event.entity.EntityEffectTickEvent(entity.getBukkitLivingEntity(), org.bukkit.craftbukkit.potion.CraftPotionEffectType.minecraftHolderToBukkit(this.effect), this.amplifier).callEvent() // Paper - Add EntityEffectTickEvent
                 && !this.effect.value().applyEffectTick(serverLevel, entity, this.amplifier)) {
                 entity.removeEffect(this.effect);
             }
@@ -408,7 +_,7 @@
                     .apply(instance, MobEffectInstance.Details::create)
             )
         );
-        public static final StreamCodec<ByteBuf, MobEffectInstance.Details> STREAM_CODEC = StreamCodec.recursive(
+        public static final StreamCodec<net.minecraft.network.FriendlyByteBuf, MobEffectInstance.Details> STREAM_CODEC = StreamCodec.recursive( // Paper - Track codec depth
             codec -> StreamCodec.composite(
                 ByteBufCodecs.VAR_INT,
                 MobEffectInstance.Details::amplifier,
@@ -420,7 +_,7 @@
                 MobEffectInstance.Details::showParticles,
                 ByteBufCodecs.BOOL,
                 MobEffectInstance.Details::showIcon,
-                codec.apply(ByteBufCodecs::optional),
+                codec.apply(ByteBufCodecs::increaseDepth).apply(ByteBufCodecs::optional), // Paper - Track codec depth
                 MobEffectInstance.Details::hiddenEffect,
                 MobEffectInstance.Details::new
             )