This is a minor patch to fix bugs with MardroemeSpawn Spores or Mutagen. and a few other cards.
Gwent Patch 0.8.37 Patch Notes
With update 0.8.37, our main goal was to address a set of important issues that have recently come to light, including the use of Mardroeme to get an auto-win after not choosing a target for the Mutagen card. This was not how we intended for the card to work and was something that required our immediate attention, because of the effect it was having on ranked play (players who abused this exploit have already been banned).
Other issues that have been addressed in update 0.8.37 include server errors caused by killing Morkvarg on 2 Strength and playing 3 Reinforced Ballistas and Redanian Elites. These actions should no longer cause the game to desynchronize.