You are using choices within flow steps with parameters such as "Member of Program" and the lead is qualifying for the choice when they are not part of the program.
When using a flow step for a campaign, you have the option of adding "choices" to the flow step so different leads can have different interactions. When using a choice parameter such as "Member of Engagement Program" or "Program Status". If the lead has been part of ANY engagement program, or has EVER had a program status equal to the parameter (i.e program status is email > sent), then the lead will qualify for that step. To prevent outside leads from being pulled in, use the "Member of Program" filter in your campaign Smart List to make sure content is delivered to your intended audience.