Unity Editor fails to load assembly but everything works fine in player build.

Hi everyone. I am trying to work with System.Text.Json in unity. I collected all dependencies and when trying to enter play mode, following exception thrown:

Code (CSharp):

1. FileNotFoundException: Could not load file or assembly 'System.Runtime.CompilerServices.Unsafe, Version=4.0.4.1, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies.
2. System.Text.Json.JsonEncodedText.Encode (System.String value, System.Text.Encodings.Web.JavaScriptEncoder encoder) (at <156be8dd8a8748a88733a94decab76f8>:0)
3. System.Text.Json.JsonSerializer..cctor () (at <156be8dd8a8748a88733a94decab76f8>:0)
4. Rethrow as TypeInitializationException: The type initializer for 'System.Text.Json.JsonSerializer' threw an exception.
5. TestBehaviour.Start () (at Assets/Scripts/TestJson/TestBehaviour.cs:10)

But when I build standalone player, everything works fine and code executed as expected.

Any additional information I can provide to solve this issue?
Thanks in advance.

 

Must to notice that all dlls located in separate folders. Moving them to same folder makes everything working fine, but that is not very desired.