Collectible Card Game Headquarters

Describe the Bug:
You can cancel spells chosen by Wild Evocation during targeting, and they just go into your graveyard.

Which card behaved improperly?
Wild Evocation.

Which update are you using? (date, name)Which type? (duel, gauntlet, sealed deck)
Dev e9d990e.

What exactly should be the correct behavior/interaction?
It says "the player casts it without paying its mana cost if able". But don't take the card's word for it, there's a ruling that says exactly the same: If a player reveals a nonland card, that player must cast that card if it’s possible to do so, even if he or she doesn’t want to. [...]

Are any other cards possibly affected by this bug?
Yes, but surprisingly few cards use this wording - just Word of Command (which isn't in Manalink), Omen Machine, and Spelltwine.

1- You can also cancel mandatory additional costs like Fling.You are asked to sacrifice a creature twice if you cancel the first prompt but both prompts are cancellable.
Also there is a problem with Wild Evocation and mandatory additional costs with mana.
2- Flamekin Bladewhirl and similar doesn't charge floating mana from mana pool.
3- Flamekin Bladewhirl and similar doesn't ask if you want to pay the additional mana cost and then be cast or not according to if you selected to pay or not.It is just cast for free without considering additional mana costs.

Ruling:
If casting the revealed card involves paying a mandatory additional cost (such as the one Fling has), the player casting that card must pay that cost if able. If he or she can’t, the card remains uncast in his or her hand. If the mandatory additional cost includes a mana payment, the situation is more complex. If the player has enough mana in his or her mana pool to pay the cost, that player must do so. If the player can’t possibly pay the cost, the card remains uncast in his or her hand. However, if the player has the means to produce enough mana to pay the cost, then he or she has a choice: The player may cast the card, produce mana, and pay the cost. Or the player may choose to activate no mana abilities, thus making the card impossible to cast because the additional mana can’t be paid.

Do these bugs happen in dev version also?