Cashed code-first model with Npgsql

I'm trying to turn on use of cached entity models (after reading https://mirkomaggioni.com/2018/01/06/performance-improvements-in-entity-framework-6-2/) along with Npgsql provider.

dbconfiguration:

Class NpgsqlConfiguration
  Inherits System.Data.Entity.DbConfiguration
  Public Sub New()
    Dim provider = "Npgsql"
    SetProviderServices(provider, Npgsql.NpgsqlServices.Instance)
    SetProviderFactory(provider, Npgsql.NpgsqlFactory.Instance)
    SetDefaultConnectionFactory(New Npgsql.NpgsqlConnectionFactory())

    SetModelStore(New DefaultDbModelStore(Directory.GetCurrentDirectory()))
  End Sub
End Class

At the first run Edmx model is generated, with valid content. However on the second run exception occurs, when i try to get access to some db sets from the context

ctx.Set(Of EntityClass).ToList()

System.ArgumentException: 'The path is not of a legal form.'

How can i overcome this? Thanks for the help.

Entity framework 6.2.0, Ngpsql 4.0.2, ef.npgsql 3.2.0