SerializeField of RuntimeAnimatorController will be Null for non-array.

[KazukiKuriyama]

When serializing RuntimeAnimatorController under the following conditions, if it is not an array, it will be treated as null even if attached.
Therefore, it seems that if you want to treat it as a serialized field at present, it must be an array.

[field: SerializeField] public RuntimeAnimatorController AnimatorController { get; set; }
[field: SerializeField] public RuntimeAnimatorController[] AnimatorControllerArray { get; set; }

■Environment
VRChat SDK : v3.7.5
Unity : 2022.3.22f1