In order to keep your budgets and reports showing accurante information, parent transactions should not be categorized and the sum of the splits should equal the parent transaction amount. If either of these are not the case, then it's possible you aren't tracking your income or expenses correctly. The Split Health Check will search for any split transactions where the aforementioned cases aren't correct.
Settings at the top right side of the page, then click on Split Health Check under the Miscellaneous Actions header.Search for Split Issues button, any problematic split transactions will be shown to you. Clicking on the View link on the left side of the transaction will take you to the Search tool where you can edit the transaction.