Comments attaching to wrong posts

Someone recently asked me about a problem they are having with comments attaching themselves to the first post in the blog despite those comments having been made to other posts.

This is his description of the problem:

The problem is that when someone adds a comment to a specific post and I moderate that post, it always attaches as a response to the first post I entered into the blog. I have one now that was entered in response based on the comment that specifically names the person in the photo “Keeping it in the family” but when I moderate it says – In response to “New blog for the ranch”

I had him try different themes, turn plugins off, etc and he says it only happens with a certain theme with the plugins both on and off. I was not able to recreate this problem myself using the theme in question on 4 different blogs.

Can a theme affect the backend of a blog? And does anyone have any idea on what causes this and how to fix it?

Edit to add that the version of wp that he’s using is 2.8.6. I selected that when making this post but for some reason it’s showing as 2.8.5.