I reported the following issue to Tumblr:
I have setup Tumblr to post to Facebook as well. However, I have noticed that posts published from the queue do not appear in my Facebook timeline - only posts I publish directly. can this please be fixed?
And this is the reply I received:
Facebook has altered the way it displays information from Tumblr and other applications. While you should see some of your posts appearing in your newsfeed, not all posts will appear there. This is to keep applications from cluttering your Facebook newsfeed.
Unfortunately, we can't control how Facebook displays content from Tumblr.
This does not sound right to me: Tumblr would surely have been the author of a plugin - and failing to post to Facebook items that came from the queue does not sound like something on the Facebook side, but in the plugin. Is it possible that I am doing something wrong here?
-edit- Why would Facebook discriminate between posts published from a queue and posts published directly? More importantly, HOW could they discriminate? Is this data provided by Tumblr to Facebook? Either way, this looks like a bug to me, and I believe it more likely that it's a bug on the Tumblr side and I am disappointed that Tumblr apparently will not even investigate.