diff --git a/pytest.ini b/pytest.ini
index 16983be5e..9df4370ec 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -26,3 +26,5 @@ filterwarnings =
     ignore:Module scrapy.utils.reqser is deprecated
     ignore:typing.re is deprecated
     ignore:typing.io is deprecated
+    ignore:::h2
+    ignore:::w3lib
diff --git a/scrapy/core/downloader/__init__.py b/scrapy/core/downloader/__init__.py
index 79c2846e1..894ba8900 100644
--- a/scrapy/core/downloader/__init__.py
+++ b/scrapy/core/downloader/__init__.py
@@ -350,6 +350,7 @@ class Downloader:
         self._slot_gc_loop.stop()
         for slot in self.slots.values():
             slot.close()
+        self._record_backout(None)
 
     def _slot_gc(self, age: float = 60) -> None:
         mintime = time() - age