I don't know what to call these features, so I'm making up names. Sunglasses meme.

You have a re-usable user interface widget to select creature types. Examples of cards using it include Vanquisher's Banner and Herald's Horn.

The flow of this widget is to offer pre-indicated relevant creature types, and to offer another device that extends this to the total creature type list.

In the most recent client, the predicate that indicates relevant creature types has been modified. There is an information leakage that gives opponent advantage to this modification.

This is guesswork, but I'm a Sliver player, so I'm inappropriately confident.

I believe that in clients prior to the one released (today?,) the predicate pre-selected the creature type(s) present in the player's deck.

For some reason, this has now been modified to include creature types present in the opponent's deck.

Notice that I did not say "creature types you have seen the opponent play."

What this means is that on round 3, I can gain significant information about what creature types the opponent has for play. This is a serious disadvantage to many deck types.

Three repairs are possible:

1. Change the predicate again, from "opponent creature types" to "seen opponent creature types."
2. Revert the predicate to "player's creature types." I assume this change was for a reason, so I assume #1 is preferable, but for the love of me I can't think of why someone would actually want this.
3. Remove blue from the game and color pie, because they're the ones getting raked here.

I noticed this because I was entering a game against what I assume must have been an Alarund player, going by the creature types I saw. This induced me to an early rush I wouldn't otherwise have gone in for, preventing them from trapping me in infinity turn mess.

I should not have known what that player had. Hidden card information is sufficiently important to have several card classes dedicated to mining it out. In game terms, "we pay for this." I was gifted it through a bug. I essentially unintentionally cheated, with the card game equivalent of a wall hack.

Please fix.