Guild Wars 2

I saw about 20 enemy players near our Supply Depot, and decided to jump from the cliff and wait some time. )
Few second later enemy-thief jumped to me. Hit my hero several times and disappeared under textures.
Is it a bug?

https://youtu.be/lzs_Um-Uohs

Unfortunately I do not have video record from the beginning.

It happened about 40 minutes ago.

Usually players underground or fast teleporting abnormal distances are usually people exploiting. In these cases you better report them via in-game tool. Also, if you see or know some type of exploit you can report it via email to exploits@arena.net.

Just to remind, reporting exploits in forums isn’t allowed and it’s discouraged. Also to remind, that email is for reporting the ways an exploit can be done, to report players for any illegal behavior you have to use the in-game tool.