Miguel DEFIED ORDER -- Singer Was Told Not to Jump At Billboard Awards

Miguel was ORDERED not to attempt a dangerous jump over the crowd during his performance at the Billboard Music Awards because producers believed it was too dangerous ... but the singer ignored them ... sources connected to the production tell TMZ.

We're told ... Miguel approached producers before rehearsals and asked if he could try to jump over the crowd during his performance ... but producers shot down the idea, telling Miguel it was just too dangerous.

But when showtime came around, Miguel blew off the order ... and producers' fears were realized when he botched the jump and leg dropped a female fan ... slamming her head against the stage.

Now, the victim's lawyer says she may have suffered a brain injury as a result ... and a lawsuit could be on the way.