diff --git a/.github/workflows/docker-build.yml b/.github/workflows/docker-build.yml
index ef05400c..ee405fb8 100644
--- a/.github/workflows/docker-build.yml
+++ b/.github/workflows/docker-build.yml
@@ -107,6 +107,7 @@ jobs:
           make test-unit
 
       - name: Run integration tests
+        id: integration-tests
         run: |
           OPENAUDIO_CI=true \
           OPENAUDIO_IMAGE=openaudio/go-openaudio:${{ inputs.tag }}-test \
@@ -114,6 +115,19 @@ jobs:
           TTY_FLAG="--no-TTY" \
           make test-integration
 
+      - name: Diagnose integration failure
+        if: failure() && steps.integration-tests.outcome == 'failure'
+        timeout-minutes: 2
+        continue-on-error: true
+        run: |
+          compose=(docker compose --file=dev/docker-compose.yml --project-name=test --project-directory=.)
+          "${compose[@]}" ps --all
+          docker stats --no-stream
+          for container in $("${compose[@]}" ps --all --quiet); do
+            docker inspect --format '{{.Name}} status={{.State.Status}} exit={{.State.ExitCode}} oom={{.State.OOMKilled}} error={{.State.Error}}' "$container"
+          done
+          "${compose[@]}" logs --no-color --tail=500
+
       - name: Shutdown
         if: always()
         run: make test-down
diff --git a/pkg/mediorum/server/transcode.go b/pkg/mediorum/server/transcode.go
index 67c23ca3..d7761763 100644
--- a/pkg/mediorum/server/transcode.go
+++ b/pkg/mediorum/server/transcode.go
@@ -523,6 +523,10 @@ func (ss *MediorumServer) transcode(ctx context.Context, upload *Upload) error {
 
 	dbUpload.TranscodeProgress = 1
 	dbUpload.TranscodedAt = time.Now().UTC()
+	// A concurrent mirror update may have restored a snapshot from before
+	// this worker's busy write. Completion owns the result and its attribution;
+	// do not inherit a missing or stale worker identity from that snapshot.
+	dbUpload.TranscodedBy = ss.Config.Self.Host
 	dbUpload.Status = JobStatusDone
 	dbUpload.Error = ""
 	dbUpload.TranscodeResults = upload.TranscodeResults
diff --git a/pkg/mediorum/server/transcode_test.go b/pkg/mediorum/server/transcode_test.go
index 59d13b4b..3d79c78c 100644
--- a/pkg/mediorum/server/transcode_test.go
+++ b/pkg/mediorum/server/transcode_test.go
@@ -2,15 +2,86 @@ package server
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"os"
 	"strings"
+	"sync/atomic"
 	"testing"
 	"time"
 
+	"github.com/OpenAudio/go-openaudio/pkg/mediorum/cidutil"
+	"github.com/OpenAudio/go-openaudio/pkg/mediorum/crudr"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+func TestTranscodeCompletionRestoresWorkerAfterStaleMirrorWrite(t *testing.T) {
+	ctx := context.Background()
+	ss := testNetwork[0]
+	id := fmt.Sprintf("transcode-attribution-%d", time.Now().UnixNano())
+	f, err := os.Open("testdata/beep.wav")
+	require.NoError(t, err)
+	defer f.Close()
+	cid, err := cidutil.ComputeFileCID(f)
+	require.NoError(t, err)
+	_, err = f.Seek(0, 0)
+	require.NoError(t, err)
+	require.NoError(t, ss.replicateToMyBucket(ctx, cid, f, []string{ss.Config.Self.Host}))
+	upload := Upload{
+		ID: id, Template: JobTemplateAudio, OrigFileCID: cid,
+		OrigFileName: "beep.wav", CreatedBy: ss.Config.Self.Host,
+		CreatedAt: time.Now().UTC(), Status: JobStatusNew,
+		PlacementHosts:   []string{ss.Config.Self.Host},
+		TranscodeResults: map[string]string{},
+	}
+	require.NoError(t, ss.crud.Create(&upload))
+	t.Cleanup(func() {
+		ss.crud.DB.Delete(&Upload{}, "id = ?", id)
+		ss.crud.DB.Where("\"table\" = ? AND data->0->>'id' = ?", "uploads", id).Delete(&crudr.Op{})
+	})
+
+	// A mirror worker can read the initial row before the transcode claims
+	// it, then write that snapshot after the busy operation. Force this order
+	// instead of relying on goroutine timing.
+	stale := upload
+	stale.Mirrors = []string{ss.Config.Self.Host}
+	var injected atomic.Bool
+	ss.crud.AddOpCallback(func(op *crudr.Op, _ interface{}) {
+		if op.Table != "uploads" || op.Action != crudr.ActionUpdate {
+			return
+		}
+		var rows []Upload
+		if json.Unmarshal(op.Data, &rows) != nil || len(rows) != 1 || rows[0].ID != id || rows[0].Status != JobStatusBusy {
+			return
+		}
+		if injected.CompareAndSwap(false, true) {
+			require.NoError(t, ss.crud.Update(&stale))
+		}
+	})
+
+	require.NoError(t, ss.transcode(ctx, &upload))
+	require.True(t, injected.Load())
+	var saved Upload
+	require.NoError(t, ss.crud.DB.First(&saved, "id = ?", id).Error)
+	require.Equal(t, JobStatusDone, saved.Status)
+	require.NotEmpty(t, saved.TranscodeResults["320"])
+	require.Equal(t, ss.Config.Self.Host, saved.TranscodedBy)
+
+	var ops []crudr.Op
+	require.NoError(t, ss.crud.DB.Where("\"table\" = ? AND data->0->>'id' = ?", "uploads", id).Find(&ops).Error)
+	for _, op := range ops {
+		var rows []Upload
+		require.NoError(t, json.Unmarshal(op.Data, &rows))
+		for _, row := range rows {
+			if row.Status == JobStatusDone {
+				require.NotEmpty(t, row.TranscodeResults["320"])
+				require.Equal(t, ss.Config.Self.Host, row.TranscodedBy)
+			}
+		}
+	}
+}
+
 func TestTruncateUploadError(t *testing.T) {
 	short := "short error"
 	assert.Equal(t, short, truncateUploadError(short))