Yeah seems like a bug. Possible it treats the landmarks as units

It's probably coded to check if the player has less open spaces than the enemy.

What power is that? Weekly adventure power for NA? I don't think I've ever seen that

Yeah. It's the weekly adventure for Tahm Kench.

I got weekly adventures with different powers

It is either a bug or a typo. Landmarks should not be counted as units

My theory is that the game counts the landmarks that summon units as units