If burning Pyrodex created any form of cyanide in a form that was harmful or deadly, Hodgdon would have had to report it in the MSDS.
Failure to do that would result in the Federal Government imposing severe penalties on Hodgdon and prohibit them from making or selling Pyrodex in any form.
Dicyandiamide; CAS No.: 461-58-5 or Cyanoguanidine aren't even listed on OSHA's online chemical database.