I shot a frost jolt at a dwarf. He Ducked it and shot it back at me. I tried to purge it, but it wasn't removed. Once an enemy steals my card, doesn't it become an "enemy-controlled card"? Some folks in the lobby said they've had similar issues when monkeys steal their cards in the campaign.
It looks like it's a graphical bug based on this old thread. The effect is actually purged but the card stays on.
