How often do planets, such as your Sun's 12th Planet, take up an orbit around two suns rather than remaining dedicated to one sun. Rarely, as this requires the wanderer to be large enough that a strong repulsion force develops when it approaches one of the suns and to also have congealed after a big bang in such a position between the two suns that this binary orbit ensues. If close to one sun it will settle into the normal orbit around this single sun. But if fairly equidistant it will approach one sun with comet like speed and return in the same direction, as comets do, to begin its binary orbit.
Are such binary orbits always disruptive to life on planets orbiting one or the other of the suns? Most certainly, depending upon the placement of the planets, angle of entry into the planetary orbital plane, and relative size of the wanderer. If the wanderer is small, its action is like a comet. If the wanderer is larger than planets it passes, then scenarios such as pole shifts can potentially occur. This likelihood is further reduced by the magnetic potential, which is strong or weak depending on the composition of the planets and wanderer. This potential is further weakened by the relative number of life bearing planets that are dry land planets, as most life bearing planets are water planets. Life in the water, during earthquakes, is not traumatized to the degree that life on land is traumatized. Water cushions any trajectories by braking the speed.
Thus the periodic trauma your Earth undergoes as a life bearing planet is quite unusual. Where this happens elsewhere in the Universe the inhabitants have reacted much as humans have - with denial beforehand and deliberate amnesia afterwards. In this, you are typical.