diff --git a/backend/api/admin.py b/backend/api/admin.py
index 98bd5e2..ee26e7e 100644
--- a/backend/api/admin.py
+++ b/backend/api/admin.py
@@ -23,10 +23,12 @@ Security invariants:
 """
 from __future__ import annotations
 
+import time
 import uuid
 from datetime import datetime
 from typing import Optional
 
+from config import settings
 from fastapi import APIRouter, Depends, HTTPException, Request, status
 from pydantic import BaseModel, ConfigDict, EmailStr, Field, field_validator
 from sqlalchemy import func, select, update
@@ -351,6 +353,12 @@ async def update_user_status(
     if not body.is_active:
         # Revoke all refresh tokens on deactivation
         await revoke_all_refresh_tokens(session, user.id)
+        # Revoke any pre-deactivation access tokens still within their TTL (T-7.2-01)
+        await request.app.state.redis.set(
+            f"user_nbf:{user.id}",
+            int(time.time()),
+            ex=settings.access_token_expire_minutes * 60,
+        )
 
     session.add(user)
 
diff --git a/backend/tests/test_admin_api.py b/backend/tests/test_admin_api.py
index 6bb819d..5e16d8a 100644
--- a/backend/tests/test_admin_api.py
+++ b/backend/tests/test_admin_api.py
@@ -450,10 +450,11 @@ async def test_delete_user_no_body(admin_client):
 # user_nbf — only deactivation writes it (RESEARCH.md anti-pattern).
 
 
-@pytest.mark.xfail(strict=False, reason="Phase 7.2 Wave 2 — user_nbf write not yet added to admin deactivation handler")
 @pytest.mark.asyncio
 async def test_deactivate_user_writes_user_nbf_to_redis(admin_client):
     """PATCH /api/admin/users/{id}/status {is_active: false} must write user_nbf:{id} to Redis."""
+    from main import app
+
     client, _admin, session = admin_client
     target = await make_regular_user(session)
 
@@ -463,11 +464,11 @@ async def test_deactivate_user_writes_user_nbf_to_redis(admin_client):
     )
     assert resp.status_code == 200
 
-    # Wave 2 will add the user_nbf write; this is the target assertion:
-    assert False, "stub — Wave 2 will fill in: nbf_bytes = await app.state.redis.get(f'user_nbf:{target.id}'); assert nbf_bytes is not None"
+    nbf_bytes = await app.state.redis.get(f"user_nbf:{target.id}")
+    assert nbf_bytes is not None
+    assert int(nbf_bytes.decode() if isinstance(nbf_bytes, (bytes, bytearray)) else nbf_bytes) > 0
 
 
-@pytest.mark.xfail(strict=False, reason="Phase 7.2 Wave 2 — activation must NOT write user_nbf (invariant guard)")
 @pytest.mark.asyncio
 async def test_activate_user_does_not_write_user_nbf(admin_client):
     """PATCH /api/admin/users/{id}/status {is_active: true} must NOT write user_nbf:{id} to Redis.
@@ -498,5 +499,5 @@ async def test_activate_user_does_not_write_user_nbf(admin_client):
     )
     assert resp.status_code == 200
 
-    # Wave 2 must preserve this invariant; this is the target assertion:
-    assert False, "stub — Wave 2 will fill in: nbf_bytes = await app.state.redis.get(f'user_nbf:{target.id}'); assert nbf_bytes is None"
+    nbf_bytes = await app.state.redis.get(f"user_nbf:{target.id}")
+    assert nbf_bytes is None, "activation must NOT write user_nbf (anti-pattern guard)"