We fixed a bug where we build an incorrect commit when multiple commits are pushed at once but the last commit contains the magic command (e.g., [skip ci]).
The previous behavior was that we go back in the commit history to look for a commit without such a comment, and if one is available, build that instead. (If none is available, the request would be rejected.) This is no longer the case; we now respect and reject the build request if the command is present in the last commit. This is useful, for example, if the user wishes to skip a build of a merge commit with the magic command.