I hope they forget to fix this when Marshadow is added with DLC (please GF ) it becomes the first VGC legal mythical. :P
(Unlikely, since it sounds like the "legendary/sublegendary" list has been subdivided, giving mythicals and ultra beasts their own category, but since mythicals have always been banned there is probably a separate vgc legality list... but maybe they'll make the same mistake there!)
I guess the Paradoxes not being legends made them rethink their approach to the OTHER group of 570 BST 'mons with weird stuff going on. Those had been legendaries by the code for 2 gens (and Crown Tundra doubled down on their legendary status), but, this time around, I expect them to work the same way Paradoxes do: Regular wild 'mons in an specific area, without warranted IVs.
Beast Ball Poipole will be a thing this time around I wager.