Sometimes Bamboo says "#n is build - null"

It's quite easy to reproduce on my test instances.

1. Create a build plan. Build type and other details don't seem to matter.
2. Check the "enable this build plan" box before clicking the "Create" button.
3. The build plan is dispatched to execute. If we click the link to the running build plan, we will get a screen like the one attached, with the navigation banner saying something like "Build: #1 is building - null".

I will try to make a video for this next time I saw it.