Repository.GetUser() should be case-insensitive against a case-insensitive server.
Line 566 of Repository.user.cs has this, which is fine for the case-sensitive server.
if (to.ContainsKey("User") && to["User"] == user)
But it should be something like this against a case-insensitive server.
if (to.ContainsKey("User") && to["User"].Equals(user, StringComparison.OrdinalIgnoreCase)
Case-sensitivity is maintained in Server.ServerMetaData.CaseSensitive.