same thing happened to me last night with my necro. i finished it, though it was a painful process. there seems to be a timer on surfaces that are outside the map, that has to run out before you are returned. so what i did was, i went down and started jumping and wasn’t returned back until i stopped. that way i was able to continue, but the worst bugged part of this mission comes after that.
—small spoiler—
two ships emerge behind you and you have to kill them, funny thing is the cannons do NOT change sides and you can’t shoot behind you. so the only way to kill them, is to bounce back the fish they throw at you. i really hope this is not intended. it took forever and the one ship on the left (looking back) didn’t even aggro me when standing near the cannons. so i had to run to the front of ship for aggro, run back to the cannon, wait for the fish, bounce it back and all over again. worst gw2 experience so far.