Evolution of some of the orbital elements on a century-long timescale, obtained via numerical integrations. Left: variations of the observable arguments of periastrons (ω_1, 2) of the inner and outer orbits (black and red, respectively). The dynamically forced apsidal motions of both orbits are well visible. The gray and orange shaded regions mark the intervals of the Kepler and the ground-based spectroscopic follow up observations, respectively. Right: inclinations of the inner and outer binaries (black and red curves, respectively). The green- and lightblue-shaded horizontal areas denote the inclination domains of the inner and outer orbits where eclipses can occur. The vertical gray area represents the domain of the Kepler observations, while the thin, black, vertical line denotes the interval of the 27-day-long TESS observations (Sector 14). As one can see, during these measurements the inner inclination (i₁) was far below the green line, and therefore the inner pair did not present any eclipses. It should be noted that the dark blue line simply stands for i_1, 2 = 90° to guide the eye.