Running multiplayer server threw this overnight on console.
SaveAll took 3.085749 ms
reanimate: saved 17 zombies
../common/singleprocesspipe_any.cpp (198) : Assertion Failed: m_Peeked.second == false || m_nEventCount > 0
Didn't have time to investigate or try logging in, restarted server OK.
Also, thanks for the UPnP true console message, handy that was
The problem I see is about the starting conditions, be it for zombie population, starting loot, loot abundance... it would be far easier to start in First Week, kill all the zombies in the neighbourhood, pile up supplies and then switch to Survival and think you're doing okay in that difficulty. You wouldn't get a proper Survival experience with such a mid-game difficulty switch. Just a personal feeling though.