I understand you have your VLAN A (10.1.1.0/24).
And you want to do an L2 extension to VXLAN B. So VXLAN B has the same subnet 10.1.1.0/24.
But you don't explain how you configure the L2 extension.
If that's NOT with L2 Bridging NOR L2 VPN, how is it done?
DImitri