Call the Bloodline bugged
While playing Midweek Magic, my opponent played Call the Bloodline. He then began to activate it, paying 1 mana and discarding a card from his hand to create a 1/1 black Vampire Knight creature token (as the card specifies). However, after he ran out of cards in his hand he was able to just pay 1 mana to create the 1/1 creature token! He did this on more than one occasion.
I expected the game to not allow him to activate the enchantment's ability since he had no cards in hand! I don't believe this was a desyncing problem as neither of us disconnected during the game (I never saw the rope timer).
I am including a screenshot of one of the activations. Please note that the Sanitarium Skeleton was not in his hand, it was in the graveyard.