Is there a bug in the system? Why did I lose 50 points for serial up-voting. Some of the voting looks strange too, like it has it was voted at the same exact time when in fact some of my questions or answers were posted on different days. Can someone look into this?
In one sense you didn't really "lose" 50 points — instead, you got 50 points that you shouldn't have gotten, and that was corrected. Someone voted on too many of your posts in too short a time, which is indicative of a sock-puppet account or a voting ring.
These votes might have been legitimate, but I would guess that it's unlikely to be reversed, since you can't infer intent from nothing more than a sequence of votes. Then again you own a significant percentage of the posts so far on this site so it might have been inevitable. Hopefully an SE employee stops by and can tell you if anything will happen.
To prevent this, everyone should be careful to spread out their votes. Don't go through one user's profile and vote on all their posts, for example.