diff --git a/scrunch/datasets.py b/scrunch/datasets.py
index b4187fa..a859008 100644
--- a/scrunch/datasets.py
+++ b/scrunch/datasets.py
@@ -2276,6 +2276,9 @@ def exclude(self, expr=None):
             expr_obj = {}
         else:
             expr_obj = expr
+
+        print(expr_obj)
+
         return self.resource.session.patch(
             self.resource.fragments.exclusion,
             data=json.dumps(dict(expression=expr_obj))
diff --git a/scrunch/expressions.py b/scrunch/expressions.py
index 5ac6a8e..9e4a98e 100644
--- a/scrunch/expressions.py
+++ b/scrunch/expressions.py
@@ -632,7 +632,7 @@ def _process(obj, variables):
             elif op == 'is_valid':
                 real_op = 'all_valid'
             elif op == 'is_missing':
-                real_op = 'all_missing'
+                real_op = 'is_missing'
 
             if op in ('is_valid', 'is_missing'):
                 if len(values) != 0:
diff --git a/scrunch/tests/test_expressions.py b/scrunch/tests/test_expressions.py
index ecc8a0c..533e178 100644
--- a/scrunch/tests/test_expressions.py
+++ b/scrunch/tests/test_expressions.py
@@ -2170,7 +2170,7 @@ def test_valid_and_missing_funcs_for_arrays(self):
         expr = 'missing(hobbies)'
         expr_obj = process_expr(parse_expr(expr), ds)
         assert expr_obj == {
-            'function': 'all_missing',
+            'function': 'is_missing',
             'args': [
                 {
                     'variable': var_url
@@ -2184,7 +2184,7 @@ def test_valid_and_missing_funcs_for_arrays(self):
             'function': 'not',
             'args': [
                 {
-                    'function': 'all_missing',
+                    'function': 'is_missing',
                     'args': [
                         {
                             'variable': var_url