I think it may be more appropriate to post here , so please excuse the double post from-https://forum-en.gw2archive.eu/forum/pvp/wuvwuv/SFR-player-under-AB/first#post847640
This is an old issue on Mesmer I reported more than 2 months ago when I glitched below the surface on a PvE map (Bloodtide Coast IIRC). It was possible ther to swim below the land across the entire map and to target and hit mobs above, whilst remaining immune to damage from the legit surface. I assume that it is also possible to plant portals in this state.
A Nets failure to fix this leaves a serious exploitable bug still open in WvWvW.
(I play Wv3 on Ranger BTW)
He who fights with monsters should look to it that he himself does not become a monster.