New campaigns can be automatically added to a certain Performance Group and then the optimization starts - see how in this article.
Here is how to undo this action:
Find the Performance Group you would like to edit. Click the “More Actions” button on the right of the Performance Group. A drop-down list appears.
2. Select “Set Default for an account”.
3. An overview of the current set up will open up. In this example a new active campaign from the Amazon Accounts “Amazon Ads Demos Account (Cosmetics)” is currently automatically optimized in the selected Performance Group.
4. To undo automatic optimization click the account name on the right site under “Selected accounts”. The Amazon account moves to the left side under the title “Available accounts”.
5. Click the “Confirm” button to confirm the setting.
6. A pop-up opens up with a summary of made changes. Review the changes and click “Confirm”.
7. The Goals page appears. Find the Performance Group you just edited. You should not see the “Default” tag anymore. From now on, new campaigns are not automatically optimized.