MID. Lethal loop interaction of "Curse of Vitality" and "Highborn Vampire" [Investigating]

Wizard Class also go on forever until i die 

This is not a bug.  The cards are working as intended and written.  Many combo players such as myself greatly enjoy card interactions like this.  If you call for every synergistic 2 or 3 card interactions like this to be nerfed/changed, it alienates a sizable subset of the player base and makes us less likely to continue playing.  Designers should keep the playstyles of various player types in mind, designing cards for all of them.

There are plenty of cards in Standard to keep Curse of Vitality + High or Vampire pairing in check.  Cards that prevent someone from gaining life, support destruction, etc.  I haven't seen this deck running rampant in TG or other events.  I see a lot more Tainted Adversary and dragon combo decks personally.  I'm not calling those "bugged" or to be changed for being too powerful.  I realize people like playing those kinds of cards/deck types and accept it as part of the MTGPQ experiences.

Anyway, those are my thoughts on this matter.  I respect that we have differing views and things we like and dislike about the game.  I hope you can also see things from the viewpoint of other player types and realize making these changes to the cards would significantly diminish their enjoyment of the game.

@JinQuiet you are purposefully ignoring the big difference here. The Crusher + Pyreling combo because of it being so low rarity meant quite a lot of players had access to it, but you could also play and trigger the loop on the very same turn meaning there didn't exist any way of stopping the loop from happening at all..

Curse of Vitality however is easily countered by many cards, just to give two examples: Roiling Vortex and Fracture. 
Fracture will destroy Curse of Vitality and Roiling Vortex will stop any lifegain..

Now please stop this incessant crusade to fix something that isn't broken and go enjoy the game ❤️

JinQuiet said:

If the Bolrac-Clan Crusher + Chandra's pyreling interaction was fixed then the Curse of Vitality + Highborn Vampire should be fixed as well.

Alternatively, if decision to leave it persists then Bolrac-Clan Crusher + Chandra's pyreling fix should be revised back.

Bolrac-Clan Crusher + Chandra's pyreling are both uncommon, Curse of Vitality is a Masterpiece. Perhaps that's the important difference.

Then again, Wizard Class is also uncommon, and it endures.

Maybe Oktagon should post some kind of guidelines on which combos are considered too powerful to exist, and which should be nerfed for the continued health of the game, to help us players understand?

I agree, Wizard Class shouldn't be considered here because you have to build the whole deck to work around it. It is an actual combo deck. A combo that only needs 2 or 3 cards to win in one turn should definitely be nerfed.

If they nerfed Devilish Valet so fast because it could win in 1 turn combined with Conqueror's Pledge. Why haven't they killed this infinite combo of Curse of Vitality + Highborn Vampire yet? Is equally easy to pull if you have the cards. You just need to drop 2 cards and immediately win. Just as easy as limiting Highborn Vampire's effect to trigger X times per turn.

Was trying out a Dakkon deck based on the Curse of Vitality combo and I discovered two minor bugs.

First: if the action that started the combo was a creature attacking, I get the loop prevention dialog box after a minute, as I should. However, if the initial trigger was Dakkon's first ability, I do not get that dialog box.

Second: when you look at the Battle Log after the match has finished, if the triggering event was a creature attacking, that attack does not show up in the log.

Full decklist is as follows:
Curse of Vitality
Whir of Invention
Highborn Vampire
Defiant Bloodlord
Epicure of Blood
Cliffhaven Vampire
Finale of Revelation
Cut Your Losses
Idyllic Tutor
Pull from Tomorrow

First: If you trigger the loop before you play a card, you do not get the loop check. The loop check only happens after you make a swap. If you cycle a card that heals you and starts the loop, it will also not ask you to stop it. IMO, this is fantastic because it'll just loop until you win. Please do not fix.

Second: The battle log is always wonky when you win with a loop. The order in which things actually happen and the order that they get spit into the battle log are not always the same.