Hi Seongmin,
out of curiosity I was wondering whether your so called tor "platform" string ("??B`?\u0001") or your tor relay [1] was generated by a modified tor installation on Windows 8 or if we are looking at some bug in vanilla tor?
thanks!
[1] https://atlas.torproject.org/#details/21E84B294794821E2898E8ED18402E45E4FC35...
descriptor containing that platform string: https://collector.torproject.org/recent/relay-descriptors/server-descriptors...