We've had 'underground' bots for some time but you could usually see their name plates even though you weren't not be able to focus them to report.

Yesterday in Thanalan (can't recall the zone, the one with Drybone) I saw invisible mining bots .. well actually I saw the 'pickaxe strike' animation and heard the sound but the toon was invisible. The 'hit' animation was completely above ground level so the character was clearly not underground, it was just totally and entirely invisible.

I stood on top of the rocks this bot was mining and could see nothing of it at all.

How am I supposed to report these SE?