I also always used "tigger" c. 1997.
Now, "n" and "t" are the same sound in terms of what happens in your mouth. "n" is just "t" pronounced with the velum left open, i.e. through the nose as well as the mouth. Since that entire section of speech was performed under his breath, the whole lot of it was nasalised, because all muscles in the mouth get less tense including the velum (whose default state is open so we can breathe). So he could very easily be saying either "tigger" or "******" and nobody would be any the wiser. Who were these auditory experts?!