Update from 3.5 to 3.6 broke Chrome refresh

Summary

Ever since the update, team members using the Mattermost-Desktop app or Chrome browser do not see new messages as they are sent, and need to manually refresh to display new content.

Steps to reproduce

This is an internal Mattermost server, on the local network, configured with Connection Security set to None. Server was migrated from 3.5 to 3.6 without changing the configuration.

Observed behavior

Interestingly, some clients using Edge, Firefox, or the mobile Android app do not have this issue. It seems related to these lines in the server log file:

[2017/01/19 08:33:31 EST] [DEBG] websocket.authTicker: did not authenticate ip=xxx.xxx.xxx.xxx:50090
[2017/01/19 08:33:31 EST] [DEBG] websocket.read: closing websocket for userId= error=read tcp xxx.xxx.xxx.xxx:8065->xxx.xxx.xxx.xxx:50090: use of closed network connection

and these lines in the client console log:

[] websocket connecting to ws://xxx:8065/api/v3/users/websocket
[] method=getFileInfosForPost status=undefined statusCode=undefined err=Error: Request has been terminated
Possible causes: the network is offline, Origin is not allowed by Access-Control-Allow-Origin, the page is being unloaded, etc.