It actually is possible, but it's based on the speed you're able to achieve it. You have to make sure all debuffs are still tacked on by the time you shatter
What are all the debuffs? I only count three.
The only possibility, and this is a stretch, is that you can consume your own shatter debuff in extreme circumstances, but I doubt it. It's a 15 second cooldown abilty with a 7 second duration, so you'd need a good 110%'ish cooldown reduction, which would be difficult to get to say the least. Maybe it's possible with flags, I dunno.
Otherwise if you get a 4x shatter it's a bug. Currently you can only shatter your own debuffs, please explain exactly how to get it if you say you can, because "all the debuffs" add up to three as far as I can tell.