Two sub-jobs S1 and S2 calling the same job A within seconds. Internally Jenkins starts the job A only once, because of the "Quiet period". For the second call Jenkins returns null for the future element (see manual for Queue::schedule: "return null if this task is already in the queue").

Because of the empty future obj Multijob ignores the status of the job and causes issues.

One example:

Job A fails and S1 stops with the status FAILED. But in sub-job S2 job A gets the status PENDING and the workflow continues whether job A fails or not.

Workflow sketch:

MainJob

• Subjob S1
  • Step 1
    • Job A -> fails, subjob s2 stops and result is failed
  • Step 2
    • Job B -> not executed (expected)
• Subjob S2
  • Step 1
    • Job A -> status pending and result ignored.
  • Step 2
    • Job C -> executed (BUG!)