After poking around in the debugger a bit I found a callstack. It looks like it happens in GameObject.Instantiate, specifically when instantiating something with an Animator.
Btw, I also had this issue on the Xbox One, and I think I fixed it by updating Unity. Obviously not an option with UWP and IL2CPP.
The top of the callstack:
UnityPlayer.dll!dynamic_array<unsigned char,1>::operator[ ](unsigned __int64) Unknown
UnityPlayer.dll!UnityEngine::Animation::RegisterAvatarBindingObjects(struct UnityEngine::Animation::AvatarBindingConstant *) Unknown
UnityPlayer.dll!UnityEngine::Animation::CreateAnimatorGenericBindingsOpt(struct UnityEngine::Animation::AnimationSetBindings const &,class Transform &,struct mecanim::animation::AvatarConstant const *,struct mecanim::animation::ControllerConstant const *,struct UnityEngine::Animation::AvatarBindingConstant const *,bool,class mecanim::memory::Allocator &,class Animator &) Unknown
UnityPlayer.dll!Animator::SetupBindingsDataSet(struct mecanim::animation::ControllerConstant const *,struct UnityEngine::Animation::AnimationSetBindings const *,struct Animator::BindingsDataSet &,struct Animator::AvatarDataSet &) Unknown
UnityPlayer.dll!Animator::CreateBindings(void) Unknown
UnityPlayer.dll!Animator::CreateObject(void) Unknown
UnityPlayer.dll!Animator::Rebind(void) Unknown
UnityPlayer.dll!Animator::AwakeFromLoad(enum AwakeFromLoadMode) Unknown
UnityPlayer.dll!AwakeFromLoadQueue::InvokeAwakeFromLoad(struct AwakeFromLoadQueue::Item *,unsigned int,enum AwakeFromLoadMode) Unknown
UnityPlayer.dll!AwakeFromLoadQueue::AwakeFromLoad(enum AwakeFromLoadMode,bool) Unknown
UnityPlayer.dll!AwakeAndActivateClonedObjects(class vector_map<int,int,struct std::less,class stl_allocator<struct std::pair<int,int>,1,16> > const &) Unknown
UnityPlayer.dll!InstantiateObject(class Object &,class Vector3f const &,class Quaternionf const &) Unknown
UnityPlayer.dll!Object_CUSTOM_INTERNAL_CALL_Internal_InstantiateSingle(struct ReadOnlyScriptingObjectOfType,class Vector3f const &,class Quaternionf const &) Unknown
UnityPlayer.dll!Object_INTERNAL_CALL_Internal_InstantiateSingle_m9_897(Object_t * __this, Object_t9_5 * ___data, Vector3_t9_54 * ___pos, Quaternion_t9_56 * ___rot, const MethodInfo * method) Line 953 C++
UnityPlayer.dll!Object_Internal_InstantiateSingle_m9_896(Object_t * __this, Object_t9_5 * ___data, Vector3_t9_54 ___pos, Quaternion_t9_56 ___rot, const MethodInfo * method) Line 941 C++
UnityPlayer.dll!Object_Instantiate_m9_920(Object_t * __this, Object_t9_5 * ___original, Vector3_t9_54 ___position, Quaternion_t9_56 ___rotation, const MethodInfo * method) Line 1248 C++
UnityPlayer.dll!StaticScriptCommands_SpawnCharacter_m13_1855(Object_t * __this, String_t * ___characterID, Transform_t9_73 * ___locator, const MethodInfo * method) Line 18968 C++