I cannot duplicate your error, so you should post the smallest and simplest program that demonstrates the error. Here is my counterexample:
Though I think that instead of relying on the type defaulting to int, you should specify that STAMP and DEBUG are int parameters (and perhaps you should not be giving them fully capitalised names either, since such names are conventionally reserved for macro names).
typedef struct ts ts;
void Write_to_Diagnostic_Log(const char * const In_String, int Error_Code,
const char * const sDiagnostic_Log_Path, ts *Time_Stamp,
const STAMP, const DEBUG);