Yes, it was as I suspected. The problem is: suppose game would send you to the next stage while skipping rewards. You will start next stage with zero willpower and die, so it does not seem helpful.
Theoretically, there could be much more rare situations where stalemate is not caused by lack of resources. For example, it may happen that the only enemy left in Lava Pit encounter is Salmander Flameraiser, but all attack cards are already exhausted by it. So neither side can deal damage despite hero being able to play cards.
Still, detecting such a situation is quite tricky. How should the game know if the player is stalemated vs intentionally stalling? I will think about this problem some more. If you have specific suggestions, please share them.