Unable to map hosts as expected

[ghost]

Set this up today for K3s and wrote a tutorial here showing how to do it with dynamic IP allocation using MetalLB.

Oddly, I'm not able to map the IP in my subnet with some entries in /etc/hosts.

This works:

192.168.112.151 rancher.local

This does not:

192.168.112.151 rancher.k3d.localhost

I understand the .local Top-Level Domain is reserved by RFC6762 for Multicast DNS. But it's not clear to me why IPs in the subnet created for my tun interface won't allow host name assignments using anything else and still successfully resolve.