Jabber Video for Telepresence & AnyConnect VPNs

I recently spent some time troubleshooting a customer's video call quality issues when their staff working from home on an AnyConnect VPN make video calls using Jabber Video for Telepresence. The symptoms include low resolution being used & frequent periods of high packet loss (upto 70%) reported by Jabber Video, despite fast Internet connections in use at both ends. After much head scratching it turns out Jabber Video doesn't get on with SSL VPNs, there's an official notice from Cisco on the matter here. My testing shows that both IPsec & L2TP/IPsec VPNs don't suffer from this problem.