You're right, the DHCP configuration is not updated automatically when the bridge is created. You'd expect it happens, so you can say it is a bug.
However, speaking generally, when an interface (ethernet, bridge, bond, vlan) with DHCP configuration wants to become part of a logical interface what should be done with its DHCP configuration?
It's a complex problem...
The hard approach could be copy the DHCP settings to the new logical interface, but what happens if more than one part has DHCP settings?
I think the simplest approach is adding a validator that prevents the conflict. The rule should be: a logical interface can be constituted by parts without DHCP configuration. If we enforce this rule in the Network page we could also copy the DHCP settings during the Samba local accounts provider configuration. In this specific scenario only one network interface is involved.
Edit: this issue was already scheduled here https://github.com/orgs/NethServer/projects/1#card-2235710