Also having this issue, only appears to be one out of 7 players that I can easily speak with, but he gets disconnected about 10 times a night, everyone else appears fine. Everyone is using the exact same client from my server, nothing custom, base trinitycore with revision from a couple days ago. (Also want to mention that there is a second PC in this person's house that works perfectly fine, no disconnects, and that is why I am not opening a github issue, I am working with them first over the next couple of nights to determine what program might be running that does these disconnects)
Server 2008 R2
2 cores
16GB Memory
250GB Drive (around 100GB free)
Nothing shows in logs anywhere that I can see.
TrinityCore rev. c7d565739b2e 2017-09-03 23:10:24 +0200 (3.3.5 branch) (Win32, RelWithDebInfo, Static)