drupal_add_js doubles up?

Hi. I'm using the drupal_add_js API function in my nodes to add specific Javascript to the page where that node is being displayed but there seems to be a little problem I'm not able to figure out.

When do this:

drupal_add_js( "var i = 0;", "inline", "header" );

I see this in my HTML page:

<script type="text/javascript">
<!--//--><![CDATA[//><!--
var i = 0;
//--><!]]>

However, when I place this in my header:

drupal_add_js( "var i = 0;", "inline", "header" );
drupal_add_js( "var j = 1;", "inline", "header" );

I see this in my page:

<script type="text/javascript">
<!--//--><![CDATA[//><!--
var i = 0;
//--><!]]>
<script type="text/javascript">
<!--//--><![CDATA[//><!--
var j = 1;
//--><!]]>
<script type="text/javascript">
<!--//--><![CDATA[//><!--
var i = 0;
//--><!]]>
<script type="text/javascript">
<!--//--><![CDATA[//><!--
var j = 1;
//--><!]]>

Both drupal_add_js function calls are printed twice. If I would add a third drupal_add_js it will triple.

Does anyone knows whats going on?

Thanks,
Luke