Just had this happen versus Ares, Mod. Storm, and Doctor Doom in a Lightning round today:
The enemy Ares cast Sunder on me and DID NOT create a Yellow countdown tile at all! There was several free yellow tiles available too.
How it happened:
Computer team just had a massive AP cascade on me, I made one match on my turn (Green to throw Patch in front for the inevitable), then on the computer’s turn I began to eat all their skills as expected.
In order: Mod. Storm used Mistress of Elements, then Lightning Storm, then Hailstorm, then Ares used his Sunder.
But this time after Patch took the Sunder damage, there was no Yellow countdown tile made even though there was maybe 3 or 4 free yellows after Hailstorm covered random tiles.
I took the initial damage, but with no countdown, there was no worry about a second hit or Ares healing himself up.
More likely: Venom dying caused the game to check for unowned countdown tiles and remove it. The core bug is that Ares dies before his skill creates the countdown, so it is created after the unowned countdown check.