During PvP combat I noticed the following:

During combat, some AoE debuffs, specifically Frostbite and Thunderclap, did not seem to target the other player. Even CAST AREA did not cause the targeting to hit PvP player. Please note, it did not generate a 'resisted' message, the messaging was identical to what you see if you cast when you are outside of combat.

Tried to Bug in game as well.