This is somewhat related to #703112: Tokens are not replaced when running token_replace more than once from within the same module & #833730: Cck block display settings override basic node settings. - at least the problem stems from a similar cause.

Background : nodewords (meta tags) now sets the meta:description by using tokens, an new token of its own called [metatags-description]
When I try to use that token, and have it configured to use "Generate the token from the node teaser", this fails in the presence of cck_blocks.

What happens is that the cck_block is being invoked a little earlier on the page, and in cck_blocks_block('view') it builds the node in 'cck_blocks' build mode, without a teaser node_build_content($node, FALSE, TRUE); and then calls token_replace($title,'node',$built_nodes[$nid]);.
This primes token module, which caches its data, to think that that node has a null teaser. Token then remembers that for the duration of the page load, so that when nodewords.module goes to find the [metatags-description] (the teaser) it returns blank.
And ... my meta tags fail.

Now ... I don't know what to blame for all this. It's obviously an edge case. Not sure if it's to do with the rendering order (I'm also using context, which tends to render things differently than expected) or whether nodewords should be told to flush the token cache.

I just don't know what to fix.

BUT, I'm not using tokens in the CCK block title anyway (perhaps the code there should check to see if there are any [] in the title before it goes to that trouble) so I've got to comment that section out for now, until we find a better solution.