I've replied to you by email, but just in case, here it goes again:

Hi, and thanks for reporting the issue.
On one hand, Gnusocial AP implementation has its glitches; on the
other, I can see lxo posts arriving fine to other servers. Even with
push-based protocols as AP, the receiving server has to keep "alive"
copies of external profiles, which can (and do) fail sometimes. The
easiest way to try and fix this is for you to unfollow lxo, wait a
minute and then follow again; that should refresh his profile in your
server. Please, do tell me if, after a day or so, no new posts from lxo
arrive, so I can try other ways of fixing the issue.