crowdfavorite/wp-social — comment on commit 77ab5173fe5488fb3a9d8e409485560ebe8964c9
File: upgrades/2.0.php line 321
By awellis13:

Because the `lock()` method does the initial increment to 1 for the master process.

https://github.com/crowdfavorite/wp-social/blob/77ab5173fe5488fb3a9d8e409485560ebe8964c9/lib/social/semaphore.php#L49-54