I have some Pokémon in my Ultra Moon save file that show up as illegal in PKHeX (I have tried 24.07.27 and 25.02.23)
These Pokémon have the OT "AIDS73" and originate from a secondhand Black2 cartridge. I used Poké Transporter to move them up to Gen 7 before wiping the save around 2018 or 2019 (I don't have an exact date) and their OT was not overwritten.
I started a new Black2 save just now with the same OT and it works, so the OT of these Pokémon wasn't hacked on the B2 cart to bypass the word filter either. They are legitimate Pokémon.
The word filter in Gen 7 does prohibit the word "AIDS", but it does not prohibit "AIDS73" as I was just able to nickname a newly hatched Nincada that, but I was not able to nickname it the former name. This means PKHeX is wrong in this specific case, because it also thinks that a legal Gen 7 origin Pokémon with the nickname "AIDS73" is illegal.
But this got me thinking...is the OT "AIDS73" prohibited by the current version of Poké Transporter, but not a previous version that I had used to transport them initially?
So I continued playing the new save until I was able to catch a Pokémon and deposit it in the PC, which is thankfully very early in these games. Then I transferred the caught Purrloin to Pokémon Bank using Poké Transporter. The Pokémon still had the same OT name in Pokémon Bank, and also when I transferred it to Ultra Sun, so PKHeX is wrong in the case of the transferred up Gen 5 Pokémon as well, regardless of whether they were transported in 2019 or 2025.
