Major Bug in TFT Season 13 Arises from a “Overpowered” Upgrade
One of the most popular new mechanics in TFT Season 13 is the Ultimate Hero Upgrade. The power of this upgrade allows 1-cost champions to be leveled up to a maximum of 4 stars. In the context of TFT Season 13, where there are many strong 1-cost champions (Violet, Draven, Powder…), this upgrade helps players easily secure victories late in the game.

However, recently, players have discovered a very serious bug related to this upgrade. Specifically, if a player moves their 3-star 1-cost champion in and selects Upgrade, this champion will revert to… 1 star.
Of course, not everyone encounters this bug. But if the bug occurs, players are almost guaranteed to lose. This is because upgrades appear in rounds 4-5 – the late game phase. If those 1-cost champions are key players, this is nothing short of a “self-destruct”.

Fans Call for Riot to Quickly Fix the Severe Bug in TFT Season 13
This is a very strong upgrade, and players will almost certainly want to use it as soon as it appears. Therefore, the emergence of such a severe bug needs to be addressed quickly and thoroughly. Even if some bugs may not significantly affect the outcome of the game, the bug related to the Ultimate Hero Upgrade can turn a player “from winning to losing”.

Currently, Riot has not commented on this bug. As it is merely an upgrade in the game, players may have to wait until this mechanism appears to verify whether Riot has resolved the issue satisfactorily.