In investigating unrelated networking issues, I found isesrv.exe is leaking many connections. netstat -o reported well over a hundred connections in CLOSE_WAIT state by the isesrv.exe process. (Such leaking of connections in CLOSE_WAIT state is typically due to not calling close() or its equivalent properly once done with a connection.)
For example if the isesrv.exe task ID (as reported by netstat -o and Task Manager in Windows 10) is 1234, the following reports the number of connections isesrv.exe leaked in CLOSE_WAIT state:
netstat -o -n | find “CLOSE_WAIT” | find " 1234" | find /c /v “”
(Incidentally, blocking isesrv.exe’s internet access using the firewall seems to make the bug more apparent, so it might help you reproduce the issue faster. I use the Windows Defender firewall, and after noticing the above, I added a new rule to block all internet access to isasrv.exe. The number of connections in CLOSE_WAIT state grew faster, and appears to have stopped at 679 connections.)
Comodo Antivirus 12.1.0.6914, Database version 31923