Missing Twitter icon

I cannot get the Twitter icons visible for my blog entry.... Central Twitter posting is enabled and also single user is allowed to post with his own Twitter account. i tried the Twitter posting (automatic and user) - everything works fine - but the Twitter icons are missing.....

It seems only to fail for my newest blog post....for other users blogs the icon is available...

Maybe you can help me and lead me in the right direction.....

Thanks for your support!