Runecrafting experience in Dungeoneering glitch
Upon release of the Dungeoneering skill, there was a glitch with the equations used to calculate Runecrafting experience inside the dungeons of Daemonheim. The experience was supposed to be exponentially reduced, but ended up becoming exponentially increased. As a result, players were able to gain millions of Runecrafting experience in the short time before it was fixed.
Jagex responded with a quick fix and rolled the game back, sparking criticism from players who weren't able to even finish their first dungeon. It is unknown if any players were banned for abusing this bug.