What's up with pull request buildbots?

[Joseph Rushton Wakeling]

On 06/03/2013 07:49 AM, Adam Wilson wrote:
> - Pull requests are tested by cloning [DMD/DRuntime/Phobos] master and merging
> the pull into it. This ensures a clean pull against master.
> - The AT must restart pull request testing every time code is merged into
> DMD/DRuntime/Phobos because of the above testing strategy.
> - If many pulls are merged into [DMD/DRuntime/Phobos] master in a given period
> of, for example a day, the AT will restart prior to completing a full test pass.
> - With the current number of open pulls the AT can complete a full testing pass
> in roughly 8 hours.
> - Each pull takes a rough average of 15 minutes to test.

What I don't understand is how the number of "pending" tests fluctuates.  Not
too long ago a pull request of mine to Phobos had passed 9, with 1 pending.  Now
it's pending 10.  I have not pushed any changes in the interim ... !