Hi @kaanayfer ,
You should be able to check, by going to: Shopify > Customers > Segments > click on “Customers who have purchased at least once”
Topic summary
Issue: A discount code intended only for customers who have purchased at least once appears to be accepted when entered by a new/non‑purchasing visitor.
Setup: The discount is configured with “Specific customer segments,” selecting the segment “Customers who have purchased at least once” (confirmed via screenshots).
Troubleshooting: Guidance provided to verify the segment via Shopify > Customers > Segments > select “Customers who have purchased at least once,” and review its definition/members. Additional screenshots illustrate where to view segment membership.
Latest clarification: Support informed the poster that with this segment restriction, the code may show as active when entered, but eligibility is enforced at checkout—an ineligible customer should not be able to complete checkout with the discount applied.
Next steps/status: Perform a full checkout test with an ineligible account to confirm enforcement, and contact Shopify Support through the Help Center for account‑specific investigation if behavior differs. No confirmed bug or definitive fix in-thread; discussion remains open. Images are used to demonstrate settings and segment views.