Hi,
1) If you have configured split tunnel Check the ACL to see its including the LAN subnet to sending the traffic or not.
2) Check the LAN side to see if its able to send the return traffic to block y.y.y.1 to the VPN Router.
3) Exclude the traffic from the LAN to block y.y.y.1 from being Natted.
Do rate helpful post.
Thanks,
Kasi.