Because of the new buffering window in Super Smash Bros. Ultimate, there’s been an uptick in unintentional buffered actions across all levels of play. Smash community star Wizzrobe has experienced this too, particularly with the way the game accepts roll inputs:
When it comes to rolls, at least, the problem likely boils down to holding shield too long. Wizzrobe breaks down the way the game is accepting these inputs in his latest video for Most Valuable Gaming, which you can check out above.
Source: Most Valuable Gaming