I inspected it and while the content of each item is being properly placed within the modal content div, clicking on any item except the first one will throw the following error:
agenda-test/:1613 Uncaught TypeError: Cannot read properties of null (reading 'classList')
at handleShowModal (agenda-test/:1613:61)
at HTMLAnchorElement.handleOpenModal (agenda-test/:1626:29)
handleShowModal @ agenda-test/:1613
This error normally happens when you're manipulating a DOM element that is not ready or doesn't exist yet.
I believe the issue might be connected to the way document.querySelector works, it will target the first element available that matches the criteria. Based on your screenshot, it looks like you're adding a listener for the click targeting the class name that is the same for all elements. Maybe trying to change your code to have unique listeners could fix this issue.
For example, if I click on any of the links(except the first one) and inspect the empty modal that shows up, I can see that it is trying to read the model content of the first post.