When you cast a vanguard from hand while song of creation is in play it doesn’t draw cards nor give mana. So the game seems to think on cast the vanguards are lands, but it doesn’t treat them as lands when drawn (the first land gain full mana effect). Pretty clearly a bug and quite annoying as it means I cant use vanguards properly with song.
This issue is now under investigation.
Thank you for the feedback!
Song of Creation still does not trigger when you play a Vanguard.
It should since Song of Creation is supposed to trigger on non-Lands being played.
This issue isn’t listed in the main bug thread.