CircleCI built skipped branch commit

Recently we have been trying to skip CircleCI builds that are unused from the beginning. We have done this by using the ignore branch feature. This has normally worked great for us and we are very happy to have this feature. However, we recently had a build generated that seemed to ignore that setting. Not sure why this happened, but I wanted to raise this issue. Hopefully we can track down this issue and avoid it in the future. Thanks for your help in advance.

Here is another example of this sort of failure. Again it should have skipped this build, but it went ahead and built it anyways.