distmaker packages wrong version of Drupal6 code

I just reproduced this on my local machine with the following steps:
-Download the latest releaser script using releaser/self-update
-Run releaser --build
-Check the resulting d6 tarball, it contains old code (not sure how old, but it doesn't include the latest commits)
-Go to path/to/workdir/4.3.beta6/export/drupal and checkout 6.x-master
-This does contain the latest commits
What gives? Tim can you think of what to check next?