Do you have a lot of fields? Before I had the problem with the same field names, my problem was that the max_input_vars setting in php was set too low (default is 1000 I believe).
Maybe you can check your php log and see if it gives you any errors about that? And if it does put something like php_value max_input_vars 3000 in your .htaccess file, or edit (if you can) your php.ini file.
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