Last week I got the next error when I was upgrading from 126.96.36.199 to 188.8.131.52
ERROR at line 1: ORA-01830: date format picture ends before converting entire input string ORA-06512: at "SYS.XS_OBJECT_MIGRATION", line 167 ORA-06512: at line 28 ORA-06512: at line 69
Because of this error the upgrade fail. It leave invalid the XML component and someone more. Look for error I found in ML/MOS the note 1958876.1. This is is a bug and it is necessary to apply an one off. After applyed it the upgrade work fine.
HTH – Antonio NAVARRO