diff --git a/nvtabular/ops/categorify.py b/nvtabular/ops/categorify.py
index 769f98512e..556e2a005a 100644
--- a/nvtabular/ops/categorify.py
+++ b/nvtabular/ops/categorify.py
@@ -1693,7 +1693,7 @@ def _encode(
     expr = df[selection_l.names[0]].isna()
     for _name in selection_l.names[1:]:
         expr = expr & df[_name].isna()
-    nulls = df[expr].index
+    nulls = df[expr].index.values
 
     if use_collection or not search_sorted:
         if list_col:
diff --git a/tests/conftest.py b/tests/conftest.py
index 0ca0ad8748..3c3ae4373b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -97,7 +97,7 @@ def assert_eq(a, b, *args, **kwargs):
 
 @pytest.fixture(scope="module")
 def client():
-    distributed = Distributed(n_workers=2)
+    distributed = Distributed()
     cluster = distributed.cluster
     client = distributed.client
     yield client