Classic (policy-based) IPsec does not take routing into account by design. IPsec policy is the only thing that determines which traffic gets encrypted and sent over the tunnel.
Actually I still have a querstion regarding this issue
The LANs at either end can communicate with each other successfully
However I am unable to get the Mikrotik router, that is one end of the IPSec VPN tunnel, to route (dstnat) incoming (internet) traffic to the other end of the tunnel ?
I figured it out : the problem was that the incoming connection didn’t belong to the LAN
therefore I had to create a srcnat rule to change the source address of the incoming connection