The Citrix Access Gateway Advanced Edition (CAG integrated into an AAC Farm) presents us with a design limitation that customers must understand so that the expectation of the level of redundancy built into the solution can be met.
Having multiple CAGs in place for failover only provides you with an automated and seamless failover mechanism for Secure Access Client (SSL-VPN) connections. This is as per design of the CAGs.
There are several limitations and issues that customers must be made aware of if using the failover CAG for access to File Resources, Web Resources, Web-Based Email, and Presentation Server Applications via Web Interface. i.e. Clientless connections.