Sources close to Soulja tell us a BET rep reached out to his manager, Miami Mike, Friday ... one day before the sold-out event, and asked him not to come because of security concerns. Everyone knows Chris and Soulja don't like each other ... there have been multiple violent threats between them.

Still, Soulja was scheduled to appear, and his face was even on promo posters.

We're told Soulja's camp tried to reassure BET there'd be no problems, but execs didn't buy it ... and cut him from the game. Chris not only showed as scheduled, but earned co-MVP honors.

Soulja, on the other hand, had to settle for BET compensating him for travel expenses.