Text on the card says, " Before you act, each character at this location must succeed at a Constitution or Fortitude 12 check, or the difficulty of that character's checks is increased by 4."

 

However, when I failed the Constitution check, I received damage, and all the cards in the character's hands were lost.

 

I'm positive I did not just misread what the check is for -- I am now looking at the screen for combat, and the required number to beat has correctly been increased from 20 to 24... but all my cards are gone.

Not too long ago, The Black Monk wasn't correctly doing its "Before You Act" check.  Perhaps the fix was a little... overzealous.  

 

Either there was some weird regression, or the internal logic on that card may be interpreting the BYA as a combat check.  Stranger things have happened...