I had this exact problem after changing the port per the guide to 8050 to avoid a conflict.
I wound up manually editing /boot/config/plugins/dockerMan/templates-user/my-binhex-qbittorrentvpn.xml and changing this line from 8080 to my chosen 8050.
<WebUI>http://[IP]:[PORT:8050]/</WebUI>
This not being updated seems like a bug ?