Yes, processing is delayed on our side today. A network slowdown between our build servers and storage provider has created a backlog affecting butler pushes, including small HTML5 patches. Builds are still processing, but with delays of several hours as of this post.
The "latest build is still processing" error is expected while the previous build on that channel is queued. At this time there's no way to cancel a pending build, but it could be something worthwhile to add in the future.
Edit: The network issue seems to be resolved, so the backlog is catching up now, some larger builds might take some time but smaller games queue is mostly processed.