Is that true though or is it just poor deckbuilding and confirmation bias? There are some examples of that but mainly in Mauve Manticore where you use premade decks. There's a lot of missions in there where it seems like they used the chance to build your own deck to counter you. Sometimes you counter yourself.
LIke, in the first Mauve Manticore 7 you have to fight the three living weapons. Your cleric has contagion and a few good things to use it on like Nimbus and Accelerated thought, but then the enemy has purging strike, punishing attacks (damage based on the number of cards in your hand) and a bunch of other ways to neutralize the advantages they built into your kit. Which is dumb. The next one gives you lots of ranged attacks to ward off invading goblins but they all draw four or five missile blocks a turn so your ranged attacks are useless, they're just there to lower the probability of your ground control moves which are actually good.
Then the zoo mission your guys have a ton of blocks to ward off the sheer number of monsters swarming you, except they also have several dropped guard and clumsy so half the time you don't even get your blocks. The mauve manticore missions in general feel designed to be awkward and difficult, more reliant on luck of the draw than strategy since whatever strategy you come up with, the enemy probably has a bunch of ways to counter it.
☑ “This guy's deck is CRAZY!”
☑ “My deck can't win against a deck like that”
☑ "He NEEDED precisely those two cards to win"
☑ “He topdecked the only card that could beat me”
☑ "He had the perfect cards"
☑ “There was nothing I could do”
☑ “I played that perfectly"