diff --git a/apiserver/apimodels/__init__.py b/apiserver/apimodels/__init__.py
index 50dcb48..c59d9cd 100644
--- a/apiserver/apimodels/__init__.py
+++ b/apiserver/apimodels/__init__.py
@@ -218,7 +218,7 @@ class ActualEnumField(fields.StringField):
         )
 
     def parse_value(self, value):
-        if value is NotSet and not self.required:
+        if value in (NotSet, None) and not self.required:
             return self.get_default_value()
         try:
             # noinspection PyArgumentList
diff --git a/apiserver/database/model/base.py b/apiserver/database/model/base.py
index 52c3dac..edc37ba 100644
--- a/apiserver/database/model/base.py
+++ b/apiserver/database/model/base.py
@@ -78,6 +78,7 @@ class GetMixin(PropsMixin):
     MultiFieldParameters = namedtuple("MultiFieldParameters", "pattern fields")
 
     _field_collation_overrides = {}
+    _numeric_collation = {"locale": "en_US", "numericOrdering": True}
 
     class QueryParameterOptions(object):
         def __init__(
@@ -708,16 +709,21 @@ class GetMixin(PropsMixin):
             if res:
                 query_sets = [cls.objects(q) for q in res]
             query_sets = [qs.order_by(*order_by) for qs in query_sets]
-            if order_field:
-                collation_override = first(
-                    v
-                    for k, v in cls._field_collation_overrides.items()
-                    if order_field.startswith(k)
-                )
-                if collation_override:
-                    query_sets = [
-                        qs.collation(collation=collation_override) for qs in query_sets
-                    ]
+            # if order_field:
+            #     collation_override = first(
+            #         v
+            #         for k, v in cls._field_collation_overrides.items()
+            #         if order_field.startswith(k)
+            #     )
+            #     if collation_override:
+            #         query_sets = [
+            #             qs.collation(collation=collation_override) for qs in query_sets
+            #         ]
+
+        # always use numeric collation
+        query_sets = [
+            qs.collation(collation=cls._numeric_collation) for qs in query_sets
+        ]
 
         if search_text:
             query_sets = [qs.search_text(search_text) for qs in query_sets]
diff --git a/apiserver/database/model/task/task.py b/apiserver/database/model/task/task.py
index 1497c19..c2c30e7 100644
--- a/apiserver/database/model/task/task.py
+++ b/apiserver/database/model/task/task.py
@@ -197,7 +197,7 @@ class Task(AttributedDocument):
             "project",
             "parent",
         ),
-        range_fields=("started", "active_duration", "last_metrics.*"),
+        range_fields=("started", "active_duration", "last_metrics.*", "last_iteration"),
         datetime_fields=("status_changed", "last_update"),
         pattern_fields=("name", "comment"),
     )