Facebook Graph API: {*actor*} not working in Caption
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I have been using Facebook Graph API to post to users' walls.  I was including the user name in the post like so:

'caption': '{*actor*} is being referenced in this example';

(This is in Python).

This was all working fine last time I checked.

Until today: now when I use this same code to post a message to my wall, I see the '{*actor*}' literal left alone, no substitution.

I know FB is notorious for changing APIs without notice.  Is this an API change, and if so what's the new policy?

Or is this just a bug on their end?