Except it IS a bug, because the condition of its effect doesn’t specify the reason for why it was sent from the field to the GY, meaning that all cases are valid (Tribute, Battle Destruction or Effect Destruction). The condition of the effect literally states:
When this card is sent from the field to the Graveyard, you can select 1 “Naturia” monster in your Graveyard, except “Naturia Eggplant”, and add it to your hand.