It seems to me that the fundamental blunder is on MBS' part.

The CIA has been pretty cozy with the Saudis ever since they were assed out of Iran in '79. That does not mean it's a respectful relationship, nor that it is one of mutual support. If I were the CIA I'd be up in MBS' business like it weren't no thang for the simple reason that he's disrupting the status quo. MBS may have underestimated the fundamental level of distrust the CIA has in South Asia, particularly when there are changes for which they are not directly responsible.

And it's possible that MBS overestimated the homogeneity of the American response. Trump feels he owns MBS; MBS feels he owns Jared Kushner. In Saudi Arabia, pretty much everyone reports to MBS (outside of splinter factions leading palace intrigue); in the US, we've got that pesky "deep state" or "continuity of government" depending on your attitude.

And I mean, the NSA has the world wiretapped. And I mean, the CIA is far, far better at surveillance and wiretapping than they are at kinetics. And I mean, if I were at the CIA I could absolutely make the case that US interests benefit by reigning in MBS via strategic leaks to Turkey.

Not sure what ambassadors have to do with it but my armchair read of the situation is that MBS thought he could get away with it and the CIA expected to profit from reminding him that he couldn't.