I'm not underestimating their influence but criminals regardless of which groups their membership/association they belong to aren't immune to internal vendetta due to personal disrespect or fallouts. Some of those cartels have splintered and usually not on good terms.
Internal vendettas happen all the time,its not rare thing at all.
The internal wars depend on how piramidal are the organization: US mafia and sicilian mafia had a commission for avoid wars where the camorra doesn't had it,some thing for the sacra corona unita while the ndrangheta had a sort of commission called camera di controllo while the Mexican cartels,they born after the Guadalajara cartel was disbanded and wasnt a boss like Felix gallardo that can keep all the bosses use him.
In some case like the scampia feud the old guards wasnt happy that the new guards take control.
