Reproduction Steps:
1. Open User's project
2. Enable Network simulator and set Simulated Packet Loss to 5%
3. Build and run Test scene
4. Run Build as a Host and join with Editor as a Client
5. Wait about 10 minutes, till the client disconnects
Note: It may differ, sometimes it disconnects instantly and sometimes it takes some time.

Expected: No disconnections, at least not under 5% packet loss

Reproduced in versions: Unity 5.4.0b15, 5.4.0b17, 5.4.0b18
Note: after ~20min wait 5.4.0b12 did not disconnect (might be Regression)

Does not reproduce on 5.3 or lower versions due to incompatible scripts.