I have a node with nodeteaser filled. When I put this code on page it works fine:

...
$node = node_load($nid);
if ($node->nodeteaser) {
...
}

But in block $node->nodeteaser is never true even If nodeteaser exists.
Also $node->teaser contain a regular teaser in this case (in block).
Thanks for you hard work. God bless you!