diff --git a/tests-assets/test_downloads.py b/tests-assets/test_downloads.py
index 9cb1b9486..cb8b36220 100644
--- a/tests-assets/test_downloads.py
+++ b/tests-assets/test_downloads.py
@@ -1,7 +1,12 @@
+import asyncio
+import uuid
+from datetime import datetime
 from pathlib import Path
+from typing import Optional
 
 import aiohttp
 import pytest
+from conftest import trigger_sync_seed_assets
 
 
 @pytest.mark.asyncio
@@ -24,6 +29,73 @@ async def test_download_attachment_and_inline(http: aiohttp.ClientSession, api_b
         assert "inline" in cd2
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("root", ["input", "output"])
+async def test_download_chooses_existing_state_and_updates_access_time(
+    root: str,
+    http: aiohttp.ClientSession,
+    api_base: str,
+    comfy_tmp_base_dir: Path,
+    asset_factory,
+    make_asset_bytes,
+    run_scan_and_wait,
+):
+    """
+    Hashed asset with two state paths: if the first one disappears,
+    GET /content still serves from the remaining path and bumps last_access_time.
+    """
+    scope = f"dl-first-{uuid.uuid4().hex[:6]}"
+    name = "first_existing_state.bin"
+    data = make_asset_bytes(name, 3072)
+
+    # Upload -> path1
+    a = await asset_factory(name, [root, "unit-tests", scope], {}, data)
+    aid = a["id"]
+
+    base = comfy_tmp_base_dir / root / "unit-tests" / scope
+    path1 = base / name
+    assert path1.exists()
+
+    # Seed path2 by copying, then scan to dedupe into a second state
+    path2 = base / "alt" / name
+    path2.parent.mkdir(parents=True, exist_ok=True)
+    path2.write_bytes(data)
+    await trigger_sync_seed_assets(http, api_base)
+    await run_scan_and_wait(root)
+
+    # Remove path1 so server must fall back to path2
+    path1.unlink()
+
+    # last_access_time before
+    async with http.get(f"{api_base}/api/assets/{aid}") as rg0:
+        d0 = await rg0.json()
+        assert rg0.status == 200, d0
+        ts0 = d0.get("last_access_time")
+
+    await asyncio.sleep(0.05)
+    async with http.get(f"{api_base}/api/assets/{aid}/content") as r:
+        blob = await r.read()
+        assert r.status == 200
+        assert blob == data  # must serve from the surviving state (same bytes)
+
+    async with http.get(f"{api_base}/api/assets/{aid}") as rg1:
+        d1 = await rg1.json()
+        assert rg1.status == 200, d1
+        ts1 = d1.get("last_access_time")
+
+    def _parse_iso8601(s: Optional[str]) -> Optional[float]:
+        if not s:
+            return None
+        s = s[:-1] if s.endswith("Z") else s
+        return datetime.fromisoformat(s).timestamp()
+
+    t0 = _parse_iso8601(ts0)
+    t1 = _parse_iso8601(ts1)
+    assert t1 is not None
+    if t0 is not None:
+        assert t1 > t0
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize("seeded_asset", [{"tags": ["models", "checkpoints"]}], indirect=True)
 async def test_download_missing_file_returns_404(
@@ -49,3 +121,48 @@ async def test_download_missing_file_returns_404(
         # We created asset without the "unit-tests" tag(see `autoclean_unit_test_assets`), we need to clear it manually.
         async with http.delete(f"{api_base}/api/assets/{aid}") as dr:
             await dr.read()
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("root", ["input", "output"])
+async def test_download_404_if_all_states_missing(
+    root: str,
+    http: aiohttp.ClientSession,
+    api_base: str,
+    comfy_tmp_base_dir: Path,
+    asset_factory,
+    make_asset_bytes,
+    run_scan_and_wait,
+):
+    """Multi-state asset: after the last remaining on-disk file is removed, download must return 404."""
+    scope = f"dl-404-{uuid.uuid4().hex[:6]}"
+    name = "missing_all_states.bin"
+    data = make_asset_bytes(name, 2048)
+
+    # Upload -> path1
+    a = await asset_factory(name, [root, "unit-tests", scope], {}, data)
+    aid = a["id"]
+
+    base = comfy_tmp_base_dir / root / "unit-tests" / scope
+    p1 = base / name
+    assert p1.exists()
+
+    # Seed a second state and dedupe
+    p2 = base / "copy" / name
+    p2.parent.mkdir(parents=True, exist_ok=True)
+    p2.write_bytes(data)
+    await trigger_sync_seed_assets(http, api_base)
+    await run_scan_and_wait(root)
+
+    # Remove first file -> download should still work via the second state
+    p1.unlink()
+    async with http.get(f"{api_base}/api/assets/{aid}/content") as ok1:
+        b1 = await ok1.read()
+        assert ok1.status == 200 and b1 == data
+
+    # Remove the last file -> download must 404
+    p2.unlink()
+    async with http.get(f"{api_base}/api/assets/{aid}/content") as r2:
+        body = await r2.json()
+        assert r2.status == 404
+        assert body["error"]["code"] == "FILE_NOT_FOUND"