This is what we thought as well, until I went back and re-read the Japanese changelog and saw the に in the description:
「相手にマーキングされている間、」
Source:
https://www.nintendo.co.jp/wiiu/agmj/update/index_260.html
At that point, we all got confused since I thought the に there was referring more to the location of where the marking occurred (at/on the opponent), rather than the other way around (from the opponent). Of course, I'm just a low elementary-level scrub, so I'm both likely and happy to be wrong; I'll actually learn from this too.