Wikipedia has a formula for the nodal period of a near-Earth satellite, taking into account the oblateness of the Earth (J2), and neglecting other effects (https://en.wikipedia.org/wiki/Nodal_period). From this formula, if the eccentricity is very small (say of the order of 1e-3 or less), I have concluded that the nodal period (Tn in Wikipedia notation) would necessarily be smaller than the period of the ideal Kepler model (no aspherity for Earth), irrespective of the value of the inclination angle i in the formula. But, this seems to contradict the teachings on Celestial Mechanics (eg https://farside.ph.utexas.edu/teaching/celestial/Celestial/node93.html, cf discussion after Eq. (10.129)). Did I miss something, or Wikipedia's formula is wrong?