diff --git a/src/_pytest/compat.py b/src/_pytest/compat.py
index d238061b4ab..b3d2cbdb669 100644
--- a/src/_pytest/compat.py
+++ b/src/_pytest/compat.py
@@ -68,7 +68,12 @@ def num_mock_patch_args(function):
     if any(mock_modules):
         sentinels = [m.DEFAULT for m in mock_modules if m is not None]
         return len(
-            [p for p in patchings if not p.attribute_name and p.new in sentinels]
+            [
+                p
+                for p in patchings
+                if not p.attribute_name
+                and any(p.new is s for s in sentinels)
+            ]
         )
     return len(patchings)
 
diff --git a/testing/test_patch_array_sentinel.py b/testing/test_patch_array_sentinel.py
new file mode 100644
index 00000000000..0bf133d7296
--- /dev/null
+++ b/testing/test_patch_array_sentinel.py
@@ -0,0 +1,15 @@
+from unittest.mock import patch
+
+
+class WeirdEq:
+    class Amb:
+        def __bool__(self):
+            raise ValueError("ambiguous truth")
+
+    def __eq__(self, other):
+        return WeirdEq.Amb()
+
+
+@patch("os.path.abspath", new=WeirdEq())
+def test_collect_ok():
+    assert True