Okay, did a quick search for the "bug". It relates to repeatedly killing task bosses for the loot, without having to kill the required number of creatures to complete the task. This actually has happened before, about 2-3 years ago.
When fighting the boss, you basically have to throw a fire bomb, wait some time for the fire to become neutral (no longer owned by you), then hit the boss to make it walk over the fields and kill it with fire. If the fire deals damage to more than half the total health of the boss, it becomes a "neutral death", meaning it was never officially killed by you. This also means you can have a second chance of killing the boss when you go back to the task NPC. So, in short, you basically go in, throw fire field, kill boss neutrally, pick up loot, leave, go back to NPC and request second chance, and repeat.
CipSoft fixed this pretty fast last time, but didn't punish anyone. Their reason for not punishing anyone was claiming it as game weakness abuse, not bug abuse. All you're doing is killing it with neutral fire, so technically it's not a bug, but a game weakness. And the game weakness abuse rule was removed long ago. So the whole abuse is legal and nobody may be punished as a result.
You should still be aware that it is a risk that you take.
Good luck.