Simplify the following text for a Grade 8 native English-speaking person.
Original: Parker 's erratic behavior ( attributable to his well-known drug addiction ) and artistic choices ( both Davis and Roach objected to having Duke Jordan as a pianist and would have preferred Bud Powell ) became sources of friction .
Simplified: Parker 's behavior was unpredictable because of his drug addiction . Davis and Roach did not agree with Parker hiring Duke Jordan as a pianist and would have preferred Bud Powell ) .