Should be resolved in the latest commit (by only writing the OT if it is modified).
https://github.com/kwsch/PKHeX/commit/1a343ead85e4fa2e9006dfec2df7b7ac38c42e5d
Thanks for bringing this to my attention
At Last! Thank You Very Much! I'm so Excited To Travel To The Original Pokémon Anime Journey Again and My Wish Will Come True! [emoji3][emoji3][emoji3][emoji3][emoji3]
Enviado de meu SM-J710MN usando Tapatalk
Edit: I'm very excited to Start My Journey On Pokémon Ultra Sun, so i gave up starting a new Journey On Yellow...
The game checks for the starter pikachu in party as follows:
https://github.com/pret/pokeyellow/blob/793c715ba253e08d2807d04d128765ca305d6b15/engine/pikachu_status.asm#L1-L46
checks TID, OT, and species ID
OT trash bytes got changed (padding zeroes overwrote the remaining spots)
Wish I'd known that three years ago. I've got about 300 of these things to re-transfer with PKHeX. But god you don't know how happy it makes me to hear that.
You kids these days with your legality checkers. Back in my day we used an untranslated Japanese program still in alpha and HxD and we were grateful.