Multiple comics per post

Hello. I use the “post” feature for uploading comics because frankly I couldn’t make the “comics” feature work for me.
I’m having a problem where if I try to change a comic in a post it just adds a comic. It does not replace it. When I go into the “edit” screen it only shows one comic, but in the live view there are many.

Here’s a screenshot. I hope it helps. Thank you.
https://i.imgur.com/cSO77Mi.jpg