There are some UTF-8 related errors on log files
Symptom: On log files there are some errors like Worker 1 stderr: Unable to convert text in character set GB18030 to UTF-8
Cause: This is almost certainly due to missing support in Perl installation for the GB18030 character encoding, a comprehensive encoding for Chinese characters.
That support requires the Encode::HanExtra module, which you can install via CPAN.