Incorrectly set IF conditions are marked with a red exclamation mark so that you can easily spot them.
You can also check if the conditions you have set are correct in the 'EDIT' - 'Questionnaire' tab by clicking on the bug icon (Check the correctness of the condition) in the 'Advanced editing settings' menu (accessed via the 'three dots' in the section above the questions). For more on how to set IF conditions correctly, check the manual.
When you activate a survey that contains incorrectly set conditions, 1KA will also warn you that the survey contains errors and where the error is located.