Hi Wayne,
For Anyconnect traffic to work through the tunnel make sure the crypto ACL for the site to site VPN tunnels have the Anyconnect traffic permitted.
You also need to make sure that correct NAT statements are in place for this traffic.
Also you need to allow the site B subnet in the split tunnel ACL in the Anyconnect group policy.
Please refer to the following discussion for more clarity:
https://supportforums.cisco.com/discussion/11106586/cisco-asa-5505-site-site-vpn-and-remote-access-vpn-problem
Regards,
Aditya