It looks like the pinned stream is ignoring my before_unix query parameter and just forking over the top of stream posts. Is this expected behavior? And does that mean I need to use a "before id" option instead?

I'm hitting: https://api.10centuries.org/content/blurbs/pins and seeing my latest pins only. That timestamp is Tue Jan 31 15:08:04 EST 2017 and matches the last pinned post fetched in a general "gimme da pins" request for my account.