Riot Games has acknowledged a bug in League of Legends where Rumble dealt less damage on the Red side compared to the Blue side, confirming suspicions that had been circulating among the player base.

League of Legends matches are divided into Blue and Red sides. Players had raised concerns regarding a 5.4% win-rate disparity for Rumble between the two sides. Specifically, it was alleged that Rumble's Q ability, 'Flamespitter', and his ultimate, 'Equalizer', dealt less damage when playing on the Red side.

David Turley, Lead Balance Designer at Riot Games, addressed the findings and future measures via his YouTube channel. He explained that the lower damage output for Rumble's Q and ultimate on the Red side was due to a 0.25-second delay in the application of skill effects.

On the Blue side, skill effects and damage register simultaneously, but on the Red side, there was a 0.25-second delay between the effect triggering and the damage being applied. Given Rumble's playstyle, which often involves enemies moving in and out of his damage zones, this 0.25-second delay accumulates, leading to a performance gap between the two sides. Such side-based advantages are a significant issue in a competitive game like League of Legends.

The development team revealed that Singed's Q ability suffered from the same issue. They noted that champions relying on ground-based persistent damage fields were particularly vulnerable to this bug. Champions like Brand and Malzahar were unaffected because their persistent damage triggers immediately upon casting, and Corki’s Q was not impacted due to its different interaction with minions.

The developers plan to fix the issues found with Rumble and Singed. The goal is to improve how damage and skill effects are synchronized to ensure identical output regardless of the side. Additionally, they are addressing other bugs, including Rek'Sai occasionally failing to traverse walls with her tunnel and issues with her Q ability attacks not registering correctly.

Turley estimated that this fix would increase Rumble's win rate on the Red side by approximately 2% to 2.5%, with a potential damage increase of 5% to 17%. He also mentioned that if Rumble is deemed too strong following these changes, he may be subject to future nerfs.