5.13.1 dev: native "Model:" block never applied on first spawn

Summary

After updating from MythicMobsPremium 5.13.0-SNAPSHOT to 5.13.1-SNAPSHOT, mobs that use the native YAML Model: block spawn without a ModelEngine model.

The vanilla entity is spawned (particles / skills still run), but MEG is never attached. /meg spawn <model> without Mythic still works, so ModelEngine and the resource pack are fine.

Environment

• MythicMobsPremium 5.13.1-SNAPSHOT (regression vs 5.13.0-SNAPSHOT)
• ModelEngine R4.1.1
• Paper 1.21.x

Reproduction

1. Define a mob with the native ModelEngine block, for example:

TestNpc:
  Type: ARMOR_STAND
  Model:
    Id: some_model
    ViewRadius: 64
    Drive: false
    DamageTint: false
  Options:
    Invisible: true
    Silent: true

2. Spawn it (/mm spawn TestNpc or a spawner).
3. Result on 5.13.1: invisible armor stand, no MEG model.
4. Same config on 5.13.0: model appears.

Using the model{} mechanic on ~onSpawn / ~onLoad still works on 5.13.1. Only the native Model: path is broken.

Expected

MobType should call this.model.apply(...) during first spawn, as in 5.13.0.