When votes are cast improperly, such as when someone misuses Stack Exchange systems, we remove those votes. Your reputation may change when votes are removed. The resulting change shows up on your reputation page as an event called “voting corrected.” Some votes are removed by an automated process that runs every day, and others are removed by staff after an investigation.
Most commonly, when a single user continually votes (up or down) on many of your posts within a short period of time, the system considers these votes to be invalid and removes them. This could happen for a variety of reasons, such as when a user finds another user’s answer great, and visits their profile to upvote many of their posts, or when a user gets into an argument with another user and downvotes their posts indiscriminately in revenge. No matter the cause, this sort of voting targeted at a person is not permitted - always remember to vote for the post, not the person who wrote it.
If such a voting pattern continues to happen - whether it’s taking place between two users mutually, from one user towards another, or otherwise falls outside of normal voting patterns - site moderators and/or Community Managers may investigate the matter further. Intentionally voting merely to reduce or inflate another user's reputation could lead to further action, such as a timed suspension from the site.
Should I be concerned about these correction statements on my profile?
No, not at all. “Voting corrected” events do not mean that you have done anything wrong. They only indicate that your reputation changed. After all, you may not have even known the votes were targeted. As long as you're not intentionally misusing the voting system to manipulate your or another user’s reputation, you do not have to worry about “voting corrected” events - they're just an indication that the system is doing its job.