Seeing CPT Post on List Page

H,

This is me second questions today. I'm sorry.

I have a created a custom post type called Campaigns. Its slug is /campaigns, and post URLs are /campaigns/my-post-url.

I have a page called Campaigns where I want to display the list of posts. The page slug is /campaigns. I've used this same configuration previously without any issues.

I can create my layout of the post list on the /campaigns page. I'm using Oxygen Builder, though I don't think that matters. However, when I view the page in the browser, I get the content of one of the posts.

Here's an example of this setup working:
Parent list page: https://vv.leapworks.dev/farmers-markets/
Child post page: https://vv.leapworks.dev/farmers-markets/dover-farmers-market/

Here's an example of the setup not working:
Parent list page: https://vv.leapworks.dev/campaigns/
Child post page: https://vv.leapworks.dev/campaigns/field-of-honor/

In the broken example, you will see the child post page content on the parent page.

Thank you very much for your help. For what it's work, I am really grateful. 🙂