Occasional 'extra' SSL port?

[Rainmaker]

I run v3.2.3 (in this case sledge's latest Mac OS X build on Yosemite 10.10.4). The listening port is mapped to a single port and qBittorrent is bound to utun0 (VPN). The vast majority of the time things appear as expected, but occasionally an 'extra' port labelled TCP_SSL shows up in the logs. I don't recognise the port number.

What is it and why is it there? I've not set it and I'm just wondering why it appears and what purpose it serves? TIA.

12/08/2015 13:38 - qBittorrent v3.2.3 started
12/08/2015 13:39 - UPnP / NAT-PMP support [OFF]
12/08/2015 13:39 - External IP: xxx.xxx.xx.xxx
12/08/2015 13:38 - Python found in PATH
12/08/2015 13:38 - Python version: 2.7.6
12/08/2015 13:38 - qBittorrent is successfully listening on interface 10.xx.x.xx port: UDP/25025
12/08/2015 13:38 - qBittorrent is successfully listening on interface 10.xx.x.xx port: TCP/25025
12/08/2015 13:38 - qBittorrent is successfully listening on interface 10.xx.x.xx port: UDP/25025
12/08/2015 13:38 - qBittorrent is successfully listening on interface 10.xx.x.xx port: TCP_SSL/4433
12/08/2015 13:38 - qBittorrent is successfully listening on interface 10.xx.x.xx port: TCP/25025
12/08/2015 13:38 - 'magnet:?xt=urn:btixxxxxxxxxxxxxxxxxxxxxxxx added to download list.
12/08/2015 13:38 - Options were saved successfully.
12/08/2015 13:38 - Embedded Tracker [OFF]
12/08/2015 13:38 - Encryption support [ON]
12/08/2015 13:38 - Local Peer Discovery support [ON]
12/08/2015 13:38 - PeX support [ON]
12/08/2015 13:38 - DHT support [ON]
12/08/2015 13:38 - Anonymous mode [OFF]
12/08/2015 13:38 - HTTP User-Agent is qBittorrent v3.2.3
12/08/2015 13:38 - UPnP / NAT-PMP support [OFF]
12/08/2015 13:38 - qBittorrent is trying to listen on interface 10.xx.x.xx port: 25025
12/08/2015 13:38 - Peer ID: -qB3230-