Is it posiable to migrate a porygon from LG/FR with Tri attack and have it carry on through breeding? I tried with a ditto and Tri attack didnt pass on...
Tri Attack it's a level up move not an egg move for Porygon. Egg moves get passed if at least the male parent know the move but level up moves only get passed if both the father and the mother know the move and the baby pokemon can learn it.
Porygon can only breed with Ditto so you can't pass Tri Attack to it.