While some crowd members continued to cheer, one pelted a water bottle at Bieber, just missing the singer's head. "Don't throw things at me, please," Bieber responded calmly.
It's not the first time "Despacito" has brought Bieber trouble: When he tried to perform the Song of the Summer contender at New York City club 1OAK in May, fans caught the singer ad-libbing "I don't know the words, so I say 'Dorito,'" in between mumbled lyrics.
Fonsi, for one, has forgiven Bieber before for messing up the lyrics, admitting himself that "the chorus is not easy to sing." And none of this has diminished the success of the song, which is currently leading the Billboard Hot 100 for the fifth consecutive week.
Watch the whole Summerburst Fest scene go down in the fan-uploaded video below: