Run records: a public run whose updated_at leaves under a second per logged step has no known end, so no 1-second duration (Search-R1's record was updated a second after it started).

results_api.py

@@ -242,10 +242,14 @@ def metric_score(r):
 
 def run_end(r):
     """When a run ended: its last attempt's end; with no attempt times, the record's updated_at, except for a public run
-    with attempts, whose updated_at may be when it was imported (its end is then not known)."""
+    with attempts, whose updated_at may be when it was imported (its end is then not known), and a public run whose
+    updated_at leaves under a second per logged step (it is not when that run ended)."""
     every_ = attempts_of(r, False); ends = [e for e in (when(a.get('finished_at')) for a in every_) if e]
     if r.get('state') == 'running': return None
-    return max(ends) if ends else None if public(r) and every_ else when(r.get('updated_at'))
+    end = max(ends) if ends else None if public(r) and every_ else when(r.get('updated_at'))
+    start = when(r.get('started_at'))
+    if public(r) and not ends and end and start and (end - start).total_seconds() < logged_steps(r): return None
+    return end
 
 
 def launch_of(name, snap):

test_public_runs.py

@@ -147,6 +147,16 @@ def test_projects_group_public_runs_by_their_project_and_org(roots):
     assert d['runs']['fixture-eval-scores']['section'] == 'evals'
 
 
+def test_a_public_run_whose_updated_at_is_not_its_end_has_no_duration(roots, client):
+    """A record updated a second after it started cannot be when a 120-step run ended: the duration is not known."""
+    fw, pub = roots
+    write(pub, 'fixture-quick-stamp', run_json('fixture-quick-stamp', started_at='2026-09-20T10:00:00Z', updated_at='2026-09-20T10:00:01Z'), metrics_rows(120))
+    fwruns._cache.clear(); R._cache.clear()
+    row = {r['id']: r for r in get(client, 'training').json()['runs']}['fixture-quick-stamp']
+    assert row['duration_s'] is None and row['ended_at'] is None
+    assert get(client, 'fwruns/fixture-quick-stamp').json()['duration_s'] is None
+    assert {r['id']: r for r in get(client, 'training').json()['runs']}['fixture-grpo-metrics']['duration_s'] == 6 * 3600   # a plausible end stays
+
 def test_an_organization_counts_the_runs_it_ran_even_in_another_organizations_project(roots):
     """A project may hold runs of several organizations (a platform's shared runs): each organization counts its own runs,
     and the project lists every organization with a run in it."""