Thank you for your reply.
I have tested many things trying to find the root cause to this problem, but I was not able to figure it out. Initially I thought it was due to a wrongly setup Tor, but I must have reinstalled Tor and followed the steps in various guides at least four times.
I think it might be due to a Tor <-> Bitcoin interaction. I've gone in the source code like here in the
stackexchange.
I'm not familiar with Mutex objects, but it seems to me that mapLocalHost and cs_mapLocalHost are not working as they are supposed to. While this relative score is not really a big deal because I still have some inbound connections and the 8 + 2 outbound, I'd be curious to understand the root cause of this behavior.
edit: Typos.