I find such Professional Nuisances are adept at rapidly increasing how irritating they are as others come to realize the PN is providing little to no business value or what value is provided isn’t enough to compensate for the irritation. Generally PNs are gossipy martyrs that thrive on bringing down others and denigrating their employer as they put up a false front of whistleblowing and/or positive disruption. A good HR team knows the signs and shows such folks the door ahead of any debacle.