Vanquish 5 Volcano Horde Zombies with Winter Greens doesn't track at all, it stays 0/5 no matter what I do.
I have tried it on volcano levels in Adventure, Lawn Patrol and Expedition (all of them completed in victory, of course). None of them works.
I double checked and confirmed that the zombies that are vanquished are Volcano Horde types (not the normal types).
I also ensured that no other plants will attack them by lining up multiple Winter Greens in 1 rows with no other plan around.
I restarted the game and tried again, still doesn't work.