The date parsing has started to fail with date-looking things. Only a…

…llow if actually allowing.

src/panoptes/utils/serializers.py

@@ -310,7 +310,7 @@ def deserialize_all_objects(obj):
                     return u.Quantity(obj)
 
     # Try to parse a ISO-8061 datetime string.
-    with suppress(TypeError, ValueError):
+    with suppress(TypeError, ValueError, KeyError):
         return date_parse(obj)
 
     return obj