You most likely have something corrupt at the main page type level for fields. You may have to dig into the database to look for the structure and look for inconsistencies since it isn't blatently obvious within the Kentico UI. The table definitions for page types are in the
cms_class table. You can look at the XML in the
Then go to the
CMS_AlternativeForm table and compare the XML in the
FormDefinition field and see how it compares to the base. Order is defined in both tables by order of the nodes in the XML.