@user_3445655 hi,
yes, it's designed like that.
for the layer 2 switching, it's not necessary to provide a mac address for the traffic because the traffic is not towarding to the switch itself.
If you capture the layer 2 swtiching packets, you'll find that the source mac address and the destination mac address both are not the switch mac address.
But for layer 3 routing, the source host and destination are in different network, the packets should be forwarded to the router or gateway, then the packets will be checked by the router, and forwarded out.