Makes sense o7. This Manaphy, for example, is illegal because it knows Scald, which is in it's BDSP moveset, A few other similar cases include Mew with Dazzling Gleam and Gliscor with Toxic.
472 ★ - Gliscor - 4152DAFE1C5A.pb8
151 - Mew - 40883AE1E29F.pb8
490 - Manaphy - B0D93AE1E29F.pb8