On a page of results, first, you have only 'More Results' link.
When you click on it, the view refreshes and a new set of results is appended (entire page not reloaded), you have both 'More Results' and 'Previous Results' link.
Then, when clicking 'Previous Results' link, the entire page is reloaded instead of refreshing only the view.
The cause of it is that the element containing the "less" link is not binded to the page by javasrcipt on the first page, thus, it will not be binded on more pages either.
A possible solution is returning both 'more' and 'less' links always, setting their container 'hidden' when it is necessary.
Therefore, I recommend the following changes in dashboard/modules/class.morepagermodule.php:
$this->CssHiddenClass = 'MorePager Hidden';
if ($Pager == '') // return $this->PagerEmpty; //delete this line return sprintf($this->Wrapper, Attribute(array('id' => $ClientID, 'class' => $this->CssHiddenClass)), $Pager); //add this line