So, a group of 5 of us have been really enjoying our first run through your mod. We're all fairly seasoned 7DtD players, and wanted something new. Initially, just for the challenge, I set the Max Spawned Zed to 70 or so, and the BM Spawn Per Player to about 40. The physical server is less than a year old, has pretty high specs, and is running 1 VM with our 7DtD game on it (Along with our 1k Science/Minute Factorio game). The server is hosted in my personal data center (I own an Internet hosting business, so I have that luxury)
And then we hit a frustrating lag issue when all 5 of us were on at one time right before the BM Horde. Turrets would take forever and a day to open, Junk Turrets would disappear when placed down, players would appear to be walking in place, and no zombies showed up.
Thinking that it was a multiplier effect from 5 people on, I scaled the BM Spawn/Player setting down to 16. It happened again last night, too. So I changed it to 8 during the several restarts that we did trying to get through our horde night. Still happened.
The lag always starts at around 18.00 or so. Restarting the server (even completely at the physical level) causes it to work very briefly, then it all happens again as the 5 of us start to log back on. Running the BM Night with 2 players seems to work just fine; 3 has generally been fine as well. 4 players is probably going to be an issue, and 5 is right out.
Once the delay starts, the logs start getting spammed with messages of Steamworks.Net NET: Received package from an unconnected client [SteamID]. Not the most helpful of error messages.
There are currently no disabled protocols in the serverconfig.xml. Most of us have issues connecting when Steamworks is disabled, per default setting, despite the server being public facing. Day count is currently at 158; party game stage is somewhere around 1300 or so. (Yay, incubi!)
It's worth noting that never had this issue with vanilla 18.4 even on this virtual server, so I assume something else is going on.