If you mean that say, the VPN client is on a network of 10.1.1.0/24, and you're also trying to connect to a network over the VPN of 10.1.1.0/24, then no, this won't work.
Theoretically it should if you're not doing split tunnelling, but the underlying Windows OS will grab the packet and send it straight out the LAN interface unencrypted, cause it thinks that you're trying to get to a local machine.