asteroids.dat is missing objects in the middle of the list, e.g. 228 and 330. https://en.wikipedia.org/wiki/228_Agathe https://en.wikipedia.org/wiki/330_Adalberta
254 as well
281 as well
296 as well
315 as well
https://en.wikipedia.org/wiki/525_Adelaide as well
https://en.wikipedia.org/wiki/531_Zerlina as well
https://en.wikipedia.org/wiki/553_Kundry as well
https://en.wikipedia.org/wiki/557_Violetta as well
https://en.wikipedia.org/wiki/574_Reginhild as well
https://en.wikipedia.org/wiki/594_Mireille as well
https://en.wikipedia.org/wiki/610_Valeska as well
https://en.wikipedia.org/wiki/641_Agnes as well
https://en.wikipedia.org/wiki/646_Kastalia as well
That's because all these objects have absolute magnitudes > 12 which are not downloaded by KStars by default. Go to KStars settings and increase the magnitude of asteroids then run update and you should have them.