If a link starts with a <BR> tag, then <BR> tag is hidden when clicking on the link, making the link exceptionally difficult to actually click on.
This happens using the HTML 4.01 Transitional doctype, in IE8, IE9, IE10 modes (it does not happen in IE7 or IE10 compatibility view).
For example, if you have this HTML:
<a href="/somewhere"><br>Click here</a>
Clicking on "Click here" will cause the "Click here" text to move as if the <br> tag did not exist. This causes the cursor to no longer be over the link, so releasing the mouse button will not follow the link.