Twisted Fate Arch Angel Interaction Bugged? Resetting Mana

I tested putting arch angel on Twisted Fate for kicks. On your initial cast of starting to pick a card you consume your mana. Arch angel kicks in here and gives you mana for the next spell. However, after you throw the card your mana seems to reset to zero., and you gotta auto back to max mana.

Is someone else observing this like me? Maybe it just looks really weird because he has two different points to casting his spell. Take note you need to observe this when he's not throwing a blue card.

Thank You!

As a side note. I feel like pick a card's speed should scale with his attack speed if it already isn't.