fallow cypress
It's an oooooooold bug, but for some reason I'm only pointing it out today. So, here goes!
Sometimes marks left by Swimming Coach's Tropical Cyclone don't disappear even after the full effect takes place.
It's probably related to the fact an enemy got KO'd and disappeared between the card activating and its effect applying, so the enemy's mark doesn't disappear since a warp didn't take place. Only a theory though, of course.
On a side note, little suggestion that probably isn't worth a post in the dedicated forum; highlighting an enemy's mark while hovering them could be a good idea to tell the players which minions are threatening their surroundings. Can be especially effective in cases where you can KO an enemy (like a post with a damaging card, or a low-health bigger minion) and prioritize going for them to save an ally, or yourself.
topaz root