So stumbled across something this evening
This code
var transaction = deserializeWorld.EntityManager.BeginExclusiveEntityTransaction();
SerializeUtility.DeserializeWorld(transaction, reader, savedState.ReferencedObjects);
deserializeWorld.EntityManager.EndExclusiveEntityTransaction();
Is crashing on windows il2cpp but not on mono builds in Entities 0.13, 2020.1, burst 1.3.3 and burst 1.4p,
I traced it all the way down to this line in EntityManagerChangeArchetype.interop.gen.cs
private static void _forward_mono_SetChunkComponent(EntityComponentStore* entityComponentStore, ArchetypeChunk* chunks, int chunkCount, void* componentData, int componentTypeIndex)
{
_bfp_SetChunkComponent(entityComponentStore, chunks, chunkCount, componentData, componentTypeIndex);
}