Sometimes, can't put my finger on it, some phases in the multi-job are not being executed.

The console log of the build clearly states:
"16:42:06 Starting build job <job_name>"
but the job isn't actually executed:
1. there is no new build of that job
2. in the summary you see "not built" (see picture)
3. the multi-job phase treats this phase as SUCCESS and thus ignores the Continuation condition.

• There are NO conditions on the step.
• This occurs in different jobs, not necessarily in the same job.
• Jobs have been created weeks ago (and were running fine).
• New builds are working as they should. (Well, most of them. I got this twice today).
• This is not reproducible manually.

Will be happy to provide more info if needed.
Thanks.