/t/ → /p/
The plosive alveolar /t/ becomes a plosive bilabial /p/ when it’s followed by a bilabial sound, such as /p/, /b/ or /m/, because of assimilation. The change only affects the place of articulation, but the manner of articulation (plosive) and the voicing (voiceless) remain the same.
Therefore,
/t/ (followed by /p/, /b/ or /m/) becomes /p/
And here are some examples taken from real life:
But, yeah, at that point I thought, “My God, I could be much more charming than Hugh!” (Rupert Everett, BBC4).
There were sources that believed that they had a hand in Philip’s assassination (Paul Cartledge, BBC4).
So, clearly, in a way, not much of a regular rythm there (Michael Rosen, OpenLearn)