To reproduce:
0) Have one computer for the editor and another for the player
1) Create a new project
2) Open Build Settings, switch to second computer's platform, enable "Development Build"
3) Build it
4) Run on the second computer
5) Open up Profiler window in the editor and connect it to the player
6) Disconnect it after a few seconds
7) Disable network from one of the computers (either by pulling the ethernet cable or turning off WiFi, depending on connection)
8) After a bit of time (~15-30 seconds, to make sure that it's registered properly), reenable network

Results: Profiler reconnects to the player even though it shouldn't.

Reproduced in 2018.3.9f1, 2019.1.1f1, 2019.2.0a13

While the customer reports getting this issue constantly, internally it could only be reproduced rarely