The incident took place on Saturday night (October 31)
The single is one of "about 700 songs" recorded for The Documentary 2
US producer teamed with Japanese trio at Ultra Music Festival
Reports of serious injuries at the September 7 pool party concert
The former friends are currently involved in public spat
Jack Ü producer admits he and his former friend have drifted apart in recent years
Grant Singer directed video revealed online
US producer released debut 'Recess' in 2014
They will be appearing at the festivals 'rave' arena The Port
The two producers will play Underworld in Camden on April 5