Usually an increase in your website’s click through rates (CTR) is a positive thing, but not if you are a Google AdSense publisher.
Some Google AdSense publishers are concerned that Google will notice the radical CTR increase and think the change to be fraudulent or illegal. If this were to happen, Google would deny any upcoming payments and ban the account.
While the fluctuations in your CTR can bring on extra stress, most AdSense publishers are saying not to worry if you see a spike because it will drop down.