mystery border in middle of the page. bizzare!

The page is here. https://stereozeitgeist.com/portfolio/?p=18

I know that the border is set to beat the top of my .lowcomment class, but what I don’t understand is why it’s so high in the page when the other ones are in place!

I have some validation errors I’m hammering out, but I don’t think any o them are pertinent to my current issue.

Here’s my comments.php if it helps.
https://pastebin.ca/1826000

Thanks in advance to whoever tells me I’m missing a slash somewhere. ??