diff --git a/test/helpers/ship-queue-fixture.ts b/test/helpers/ship-queue-fixture.ts
index 0051fd548..87068b348 100644
--- a/test/helpers/ship-queue-fixture.ts
+++ b/test/helpers/ship-queue-fixture.ts
@@ -98,10 +98,18 @@ export function ghQueueShim(repo: FixtureRepo, data: { prs: Record<string, unkno
   return { PATH: `${dir}:${process.env.PATH ?? ''}` };
 }
 
-/** A coordinator's separate clone of the fixture origin. */
+/**
+ * A coordinator's separate clone of the fixture origin, fetched through git's
+ * transport (--no-local) like a real clone of GitHub. A local clone copies
+ * origin.git/objects entry by entry, and every push into the fixture origin
+ * leaves a detached `git maintenance run --auto` there that creates and
+ * deletes objects/maintenance.lock after the push returns: local transport
+ * drops the shard's GIT_CONFIG_COUNT maintenance-off backstop, so it never
+ * reaches that receive-pack.
+ */
 export function coordinatorClone(repo: FixtureRepo): string {
   const dir = path.join(repo.root, 'coordinator');
-  const r = spawnSync('git', ['clone', '-q', repo.origin, dir], { timeout: 60_000, env: { ...process.env, ...repo.env } });
+  const r = spawnSync('git', ['clone', '-q', '--no-local', repo.origin, dir], { timeout: 60_000, env: { ...process.env, ...repo.env } });
   if (r.status !== 0) throw new Error(`clone failed: ${r.stderr?.toString()}`);
   return dir;
 }
diff --git a/test/ship-queue-train.test.ts b/test/ship-queue-train.test.ts
index 3ad14c6a8..5691f2bc5 100644
--- a/test/ship-queue-train.test.ts
+++ b/test/ship-queue-train.test.ts
@@ -59,6 +59,15 @@ function publishMain(fx: TrainFixture, prefixCommit: string, version: string, ex
   return repo.git('rev-parse', 'HEAD');
 }
 
+// fails_when=coordinatorClone copies origin.git/objects file by file again, so an entry that appears or vanishes there mid-copy (the detached maintenance.lock every push into the fixture origin leaves) fails the clone, as in Free Tests 40667144783 and 40691467553; why_new=no other test clones while origin's objects directory changes; seam=a dangling symlink planted under objects/, which a local copy refuses on every run; no_claim=which process removed the loose object those runs named
+test('the coordinator clone reads origin through git, never by copying its objects directory (GSTA-139)', () => {
+  const fx = make();
+  fs.symlinkSync(path.join(fx.repo.root, 'gone'), path.join(fx.repo.origin, 'objects', 'maintenance.lock'));
+  const coord = coordinatorClone(fx.repo);
+  expect(spawnSync('git', ['-C', coord, 'rev-parse', 'origin/main'], { encoding: 'utf8', timeout: 30_000, env: { ...process.env, ...fx.repo.env } }).stdout.trim()).toBe(fx.repo.git('rev-parse', 'origin/main'));
+  expect(fs.existsSync(path.join(coord, '.git', 'objects', 'maintenance.lock'))).toBe(false);
+});
+
 describe('the train command surface', () => {
   test('train with no subcommand (flags only) prints the train help and exits usage; --help exits 0; bad arguments name what is missing', () => {
     const fx = make();