Bebop’s insiders interrupting one of Stones, who are troublemakers (4,3,4)
I believe the answer is:
rock the boat
'are troublemakers' is the definition.
(people who rock the boat are troublemakers)
'bebop's insiders interrupting one of stones who' is the wordplay.
'insiders' says to take the centre.
'interrupting' indicates putting letters inside.
'one of stones' becomes 'rock'.
'who' becomes 'that'.
The middle letters of 'bebop' are 'ebo'.
'rock'+'that'='rockthat'
'ebo' going inside 'rockthat' is 'ROCK THE BOAT'.
(Other definitions for rock the boat that I've seen before include "It is sung" , "Disturb the status quo" , "Disturb settled position" , "make waves" , "Create waves" .)