libopenobex is available in portage as version 1.2. however, emerge --update sometimes reverts to version 1.0.1 as a dependency (possibly from obexftp? I'm not certain)
openobex 1.2 is not marked stable and the stable obexftp 0.18 obviously doesn't work with this version. If you use an ebuild which is marked testing, it's up to you to ensure all (reverse) dependencies are fine.