I have this case:
It turns out that I have a function in a package in oracle which returns a string of 4 characters
: 
but when executing the function from visual studio with the same parameter of entering the same server, the result is:
I have tried everything, change the size of the chain, the data type, etc etc etc, but I still continue cutting the output chain.
I solved it in this way, the explanation I could not find it but I got out of that mess, but I thought it was something from the application server since only in development was this inconsistency.
SQL.Append("Select PAQUETE.Funcion('"+Parametro+"') from dual");
CMD = CNX.CreateCommand();
CMD.Connection = CNX;
CMD.CommandText = SQL.ToString();
CMD.CommandType = CommandType.Text;
if (CNX.State == ConnectionState.Closed)
CNX.Open();
string a = CMD.ExecuteScalar().ToString();
return a;
}
catch (Exception)
{
throw;
}
finally
{
CNX.Close();
}
}'