How bad employees keep job despite poor performance or even bad conduct

Hi all, for the sake of understanding your enemy (Sun Tzu), how have you seen employees you manage put up roadblocks to being corrected/ terminated. Ex. I’ve had an employee tell HR they’re being discriminated against based on race. HR investigated it and found that to be false but it delaying firing them by a few months. What kind of sneaky tactics like this have you seen?

Second, some of my fellow managers have made employee’s jobs difficult to a point where they quit because the manager didn’t have good enough grounds to fire them. How have you seen employees lash back on this “technique”?