I found something strange, not sure if it's an error or not...
I have an Uxie caught in SwSh, it was modified to be shiny months ago, by ctrl + click the shiny box. At the time I didn't know that Max Lair Pokemon has PID/IV correlation, but the action still made it legal shiny.
I transferred it from SwSh to SV and eveyrthing was good.
Now that I know about the PID/IV correlation of Max Lair Pokemon, I check it again to be sure and has a very strange result:
If I dump it as pk9, it is legal in SV but becomes illegal when I open the file in SwSh setting.
I move it back to SwSh to dump as pk8 and it is legal in both pkhex settings.
Also, for any Max Lair Pokemons/Legendaries, I cannot change EC, HT, WT, IV due to the correlation. But if I ctrl+click the shiny box first making it Shiny XOR=1, all other data can then be changed freely. It isn't susposed to be like that, is it?
0480_-_Uxie_-_63665D09F87B.pk8
0480_-_Uxie_-_B8585D09F87B.pk9