diff --git a/backend/tests/test_local_dev_loopback_bind.py b/backend/tests/test_local_dev_loopback_bind.py
index 84eec16ea7..47295b86e5 100644
--- a/backend/tests/test_local_dev_loopback_bind.py
+++ b/backend/tests/test_local_dev_loopback_bind.py
@@ -246,7 +246,7 @@ def test_default_bind_host_removes_a_config_rendered_for_an_earlier_bind_host(ch
     result = _run(checkout, bind_host)
 
     assert result.returncode == 0, result.stderr
-    assert Path(result.stdout.strip()) == (checkout / "docker" / "nginx" / "nginx.local.conf").resolve()
+    assert Path(_normalize_rendered_path(result.stdout.strip())) == (checkout / "docker" / "nginx" / "nginx.local.conf").resolve()
     assert not rendered.exists(), "a stale render with the old listen lines should not be left behind"
 
 
diff --git a/backend/tests/test_multi_worker_run_ownership.py b/backend/tests/test_multi_worker_run_ownership.py
index 645c702224..f9e1a9402b 100644
--- a/backend/tests/test_multi_worker_run_ownership.py
+++ b/backend/tests/test_multi_worker_run_ownership.py
@@ -972,6 +972,10 @@ async def test_transient_renewal_exception_before_deadline_keeps_run_alive():
         return await original_update_lease(*args, **kwargs)
 
     store.update_lease = fail_once_then_renew
+    # Keep the confirmed deadline inside the 30-second lease window. Renewal
+    # computes a fresh now+lease value; Windows' coarse clock can otherwise make
+    # two immediate samples identical and defeat the strict > below.
+    record.lease_expires_at = (datetime.now(UTC) + timedelta(seconds=10)).isoformat()
     original_expiry = record.lease_expires_at
 
     try:
diff --git a/backend/tests/test_project_documents_repo.py b/backend/tests/test_project_documents_repo.py
index 2f4f28999c..894b5c8cb4 100644
--- a/backend/tests/test_project_documents_repo.py
+++ b/backend/tests/test_project_documents_repo.py
@@ -11,7 +11,7 @@ concurrent upload vs project delete, and concurrent duplicate upload.
 from __future__ import annotations
 
 import asyncio
-from datetime import UTC, datetime
+from datetime import UTC, datetime, timedelta
 
 import pytest
 
@@ -137,6 +137,23 @@ class TestReadsFilterTrashed:
         assert total == 0
 
 
+async def _stamp_updated_at(docs: ProjectDocumentRepository, stamps: dict[str, datetime]) -> None:
+    """Pin ``updated_at`` so ordering tests do not depend on the wall clock.
+
+    Rows inserted back to back can share a timestamp on hosts with a coarse
+    clock (Windows ticks at ~15.6 ms), which silently falls through to the
+    ``id`` tie-break.
+    """
+    import sqlalchemy as sa
+
+    from deerflow.persistence.projects.model import ProjectDocumentRow
+
+    async with docs._sf() as session:
+        for doc_id, updated_at in stamps.items():
+            await session.execute(sa.update(ProjectDocumentRow).where(ProjectDocumentRow.id == doc_id).values(updated_at=updated_at))
+        await session.commit()
+
+
 class TestShelfSnapshot:
     async def test_ordering_is_updated_desc_id_asc_with_one_round_trip_shape(self, repos):
         projects, docs = repos
@@ -146,13 +163,10 @@ class TestShelfSnapshot:
             rows.append(await _insert(docs, project["id"], sha=f"{i}" * 64, name=f"f{i}.txt", doc_id=f"d{i}"))
         # Re-touch d2 so it becomes the most recently updated row.
         await _insert(docs, project["id"], sha="e" * 64, name="f5.txt", doc_id="d5")
-        import sqlalchemy as sa
-
-        from deerflow.persistence.projects.model import ProjectDocumentRow
-
-        async with docs._sf() as session:
-            await session.execute(sa.update(ProjectDocumentRow).where(ProjectDocumentRow.id == "d2").values(updated_at=datetime(2999, 1, 1, tzinfo=UTC)))
-            await session.commit()
+        base = datetime(2026, 1, 1, tzinfo=UTC)
+        stamps = {f"d{i}": base + timedelta(seconds=i) for i in range(6)}
+        stamps["d2"] = datetime(2999, 1, 1, tzinfo=UTC)
+        await _stamp_updated_at(docs, stamps)
 
         snapshot_rows, total = await docs.shelf_snapshot(project["id"], limit=3, user_id="u1")
         assert total == 6
@@ -168,6 +182,8 @@ class TestShelfSnapshot:
         project = await _project(projects)
         for i in range(7):
             await _insert(docs, project["id"], sha=f"{i}" * 64, name=f"f{i}.txt", doc_id=f"d{i}")
+        base = datetime(2026, 1, 1, tzinfo=UTC)
+        await _stamp_updated_at(docs, {f"d{i}": base + timedelta(seconds=i) for i in range(7)})
         seen: list[str] = []
         offset = 0
         while True: