Why does EF Core treat the conversion method of HashSet<int> differently?

[zms9110750]

		/*	
			modelBuilder.Entity<TestEntity>()
			   .Property(e => e.ArrayProperty)
			   .HasConversion(v => JsonSerializer.Serialize(v, (JsonSerializerOptions)null!),
			 s => JsonSerializer.Deserialize<HashSet<int>>(s, (JsonSerializerOptions)null!)!);
		*/
			modelBuilder.Entity<TestEntity>()
			   .Property(e => e.ArrayProperty)
			   .HasConversion(v => v.Select(s=>s),
			 s => s.ToHashSet());
//Unhandled exception. System.InvalidOperationException: The type 'HashSet<int>' cannot be used as a primitive collection 
//because it is not an array and does not implement 'IList<int?>'. Collections of primitive types must be arrays or ordered lists.

The above code is workable.
The following code is not workable.
But it's very strange. IEnumerable should be valid.
Because this code passes and is valid.

modelBuilder.Entity<TestEntity>()
	.Property(s => s.PPT)
   .HasConversion(s =>  (s.Values.Select(s => s.ID))
   , s => s.Select(s => TestEntity4s.First(l => l.ID == s)).ToDictionary(s => s.ID));

[huoyaoyuan]

Please post EF Core questions to https://github.com/dotnet/efcore.