Are these internal connections? If so, any reason you have tunneling enabled? Tunneling makes the user connection "tunnel" through the connection server, which introduces overhead. Also, if the connection server gets rebooted, the user connection dies. This can make maintenance a nightmare. If you're doing UAGs or Access Points for external access, you need tunneling disabled anyway.
If you need to keep it enabled, you'll want to ensure the Connection Server certificate matches the one on the F5 VIP (assuming you're terminating SSL on the F5), which should also have the names of your Connection Servers in the certificate's Subject Alternative Names.
-Nick
