Game Mechanics: Nature's Defender proc is broken

[bonemender]

As the title suggests i believe the proc resist is not working properly. In PvE the proc seems to always land. However being that it has a -100 MR check, it hasn't landed once in pvp! I've tested it many times, last being on a lower lvl clr with 87 MR total. So at neg 17 MR it got resisted. If someone would look into it I would be greatly appreciative. Thanks!