Some where between 4.50 and 4.5.2 and 4.6.0 node words broke.
I didn't discover it until I couldn't get nodewords to work in 4.6.0 rc .
Did the API  change at 4.5.2 ? 
The data continues to be written to the database but I cannot read it anymore. I am using the chameleon-marvin theme.
 
If I force a string in to $nodewords it displays correctly.  ($nodewords = "some keyword data")
it appears that  "$nodewords = module_invoke('nodewords', 'get', $nid);" Is not working.
 
I am completely lost on this, any help would be appreciated. Here is the relevant code

$nodewords = module_invoke("nodewords", "get", $nid);

if (preg_match("!^node/view/(\\d+)$!", $_GET['q'], $tmp_nid)) {

if (!($words = nodewords_get($tmp_nid[1]))) {

$words = "internet marketing";

} }

$output .= '<' . 'meta name="keywords" content="' . $nodewords . '">';