I am about 80% sure that the OpenBSD builders, both 6.8 and 7.0, are timing out running all.bash. We have a hard 30 minute limit on build VMs, and the OpenBSD builders take slightly longer than that to run all.bash from scratch. However, they write a snapshot of the distribution after it's built, and reusing that saves enough time for the build to succeed upon retry -- that's why the dashboard is relatively clean-looking.
This is wasteful. We should probably increase the timeout so that the build finishes, prevent the retry, or modify the OpenBSD tests somehow to run in a more reasonable amount of time.