After getting accused twice that I use a macro to exploit the game, even though I clearly don’t, I decided to look up in to the claims.
I will not detail how this is done, though I have seen a couple of mesmers using it on purpose while some others ( like myself ) could have used it just because they are very fast on their keyboard. I have reported it trough the ingame bug reporting tool with details on how the developers can reproduce it.
For those that got hit by me with these kind of shatters, my apologies it was not intended, it’s just bad mechanics on Anet part.
*No external program, no fancy macro keyboard has been used. *
I use a A4Tech X7 G600 keyboard and a A4Tech X7 XL-747H mouse that don’t have any programming software or something like that.
Check the attached screenshot.
P.S. See a reply down below for same big shatters on Heavy Golem.
Just for the clarification, the bug increases damage per shatter by 500-1k.