diff --git a/ami/jobs/tasks.py b/ami/jobs/tasks.py
index 181b45301..dbf57fa38 100644
--- a/ami/jobs/tasks.py
+++ b/ami/jobs/tasks.py
@@ -282,6 +282,7 @@ def process_nats_pipeline_result(self, job_id: int, result_data: dict, reply_sub
         # State keys genuinely missing (the total-images key returned None).
         # Ack so NATS stops redelivering and fail the job — there's no state
         # left to reconcile against.
+        _log_missing_state_context(job_id, "process")
         _ack_task_via_nats(reply_subject, logger)
         _fail_job(job_id, "Job state keys not found in Redis (likely cleaned up concurrently)")
         return
@@ -364,6 +365,7 @@ def process_nats_pipeline_result(self, job_id: int, result_data: dict, reply_sub
             # State keys genuinely missing (total-images key returned None). Ack
             # first so NATS stops redelivering a message whose state is gone,
             # then fail the job. Mirrors the stage=process missing-state path.
+            _log_missing_state_context(job_id, "results")
             _ack_task_via_nats(reply_subject, job.logger)
             _fail_job(job_id, "Job state keys not found in Redis (likely cleaned up concurrently)")
             return
@@ -434,6 +436,46 @@ def _fail_job(job_id: int, reason: str) -> None:
         cleanup_async_job_resources(job_id)
 
 
+def _log_missing_state_context(job_id: int, stage: str) -> None:
+    # Diagnostic for a missing progress-state key. Status + age separate the two
+    # cases: a terminal job means a late result arriving after the job finished
+    # (benign — e.g. a cancel already cleaned up the state); a still-running job
+    # with no state is the one worth investigating (state never seeded, or wiped
+    # by a re-dispatched run). Observation only; the fix is planned in #1337.
+    from django.utils import timezone
+
+    from ami.jobs.models import Job, JobState  # avoid circular import
+
+    try:
+        job_values = Job.objects.values("status", "created_at").get(pk=job_id)
+    except Job.DoesNotExist:
+        logger.warning("Job %s: progress state missing and the job no longer exists (stage=%s).", job_id, stage)
+        return
+
+    age = (timezone.now() - job_values["created_at"]).total_seconds() if job_values["created_at"] else None
+    age_s = round(age, 1) if age is not None else None
+
+    # Mirror _fail_job's no-op set: a job that is already terminal OR cancelling
+    # will not actually be failed, so a late result for it is expected cleanup,
+    # not an anomaly.
+    if job_values["status"] in {JobState.CANCELING, *JobState.final_states()}:
+        logger.info(
+            "Job %s: result arrived after the job already finished (status=%s, stage=%s); ignoring.",
+            job_id,
+            job_values["status"],
+            stage,
+        )
+    else:
+        logger.warning(
+            "Job %s: progress state missing while the job is still running "
+            "(status=%s, stage=%s, age=%ss); marking it failed.",
+            job_id,
+            job_values["status"],
+            stage,
+            age_s,
+        )
+
+
 def _ack_task_via_nats(reply_subject: str, job_logger: logging.Logger) -> bool:
     """
     Acknowledge a NATS task. Returns True only when JetStream confirmed the ack.
@@ -653,6 +695,16 @@ def _update_job_progress(
                 # Advance summary.status only when the transition fired, else an
                 # already-terminal job's JSONB would disagree with its column.
                 job.progress.summary.status = complete_state
+            else:
+                # Work completed but the guard found the job already terminal/CANCELING,
+                # so the completion was not applied. Usually legitimate (a cancel or the
+                # reaper won the race); if frequent it points to a premature terminal
+                # verdict. Observation only; see #1337.
+                job.logger.warning(
+                    "Stage '%s' completed but the job was already in a terminal state; not applying %s.",
+                    stage,
+                    complete_state,
+                )
 
         # status/finished_at are deliberately NOT in this save() — only the
         # guarded UPDATE above writes them. Folding them back in reopens #1337.