LUN-1070 -- 0013 migration contains only the caption_text column truncation from 255  chars to 140. On some mysql instances, when running this migration it may exit with a warning saying "Data truncation .....". Despite the warning and the exit, the migration is considered successfull (it is recorded in south_migration_history db), but subsequent migrations won't run. When this happens, the django-admin migrate command has to be ran again.