Riot micropatched a mana glitch in League of Legends following Patch 13.6, yet, the hotfix caused an even worse issue regarding mana.
The adjustments that went live on March 24 fixed a bug that allowed players to undo selling Delivery Biscuit, which permanently increased their maximum mana. Now, the bug works in another direction, decreasing players’ maximum mana if they undo item purchases after getting a biscuit, according to League’s developer team on Twitter.