Walter suggested in a comment below to move the line after the post time + comments line for all posts of this page's template. He was right, it was a design flaw and a few times readers ended up posting comments to the wrong item.

All it takes is move the HR in the #itemTemplate file and publish again all pages of the blog.

But "all pages" for me means a lot of pages in 14 different categories, while this template only applies to 2 sites/categoreis: none of the default Radio > Publish commands applied to what I needed. So, if you need to publish all daily pages of specific Radio category, open your terminal, cd to your Radio UserLand/categories/* folder and then type:

touch 2002/*/*

After a few seconds Radio will upload all daily pages of that specific category.