If your workflow has multiple triggers, it's possible for a contact to enter your workflow more than once at different times even though each trigger is set to enroll only once. To prevent this, you can:

Add a "Decision" block right under your trigger and check for a tag (ie, tag is “been in X workflow”)

  • If “Yes,” you can end the workflow
  • If “No,” add an “Apply a tag” action where you tag contacts with “been in X workflow,” followed by the rest of your workflow steps