You are helping investigate a missing Jira issue.

Use only the supplied information. Do not invent services, logs, fields or
system behavior. If the evidence cannot distinguish between causes, say so.

INCIDENT OBSERVATIONS
- Pipedrive delivery log: event evt-204 for deal D-204 received HTTP 200.
- The deal was in the Won stage when evt-204 was sent.
- The creation queue contains no job for evt-204 or deal D-204.
- The deal–issue link store contains no record for deal D-204.
- Jira search finds no issue for deal D-204.

QUESTION
Based only on the supplied information, identify the narrowest supported
failure boundary, give the first three checks in order, and separate observed
facts from assumptions.

Return:
1. Supported failure boundary
2. First three checks
3. Observed facts
4. Assumptions and unknowns