If we do cp /usr/share/zoneinfo/Europe/Brussels /etc/localtime during install, then updating sys-libs/timezone-data do not affects current timezone info. Should create symbolic link instead of. Reproducible: Always
*** This bug has been marked as a duplicate of bug 143296 ***
*** This bug has been marked as a duplicate of bug 127899 ***
configure your /etc/timezone properly and it isn't an issue