Link Issue

You’re CSS rule looks like:

.entry p a, blockquote a {
border-bottom:1px dotted #999999;
color:#000000;
text-decoration:none;
}

The links that aren’t underlining are not contained within a paragraph, so the above rule isn’t applying to them.

the ‘more’ tag of that particular post was inserted between two images in a span, and not in a paragraph – therefore the link style does not get applied (as @skylar_inmotion already pointed out).

you could extend the link style to a.more-link– see following styles:

.entry p a, blockquote a, a.more-link {
   color: #000000;
   text-decoration:none;
   border-bottom: 1px dotted;
   border-bottom-color:  #999;
	}

.entry p a:hover, blockquote a:hover, a.more-link:hover {
   color: #cccccc;
   text-decoration:none;
   border-bottom: 1px dotted;
   border-bottom-color: #999;
	}

hope, you see the difference, and are able to edit the style.css of your theme accordingly.