When Chanukkah falls in Shabbat Torah reading "Miketz", we do not read the regular Haftarah, but read instead Haftarah for Shabbat Chanukkah. But this situation happens so often, that the next regular Haftarah is in year 5781 (2020)! Why?

True, there is no specific reason for this, but when the Haftarot were chosen they made sure every Parsha has a special Haftara, dealing with the same matters in the Parsha, whether it's read or not. Rabbi Ro'i Margalit