I wonder whether someone could give me some advice. I have been noticing several days that after being in the leaderboard for a few hours within the top 30-40, suddenly disappear from the list even though there are less than 100 stackers in the list.

Is it due to someone downzapping my post or comments? Almost in a daily basis?

After a while, and zapping some posts or comments, I manage to go back to the list though.

Not sure whether there is other explanation for this.