Using DHCP on a bridge with NixOS 24.11? No longer getting an IP? dhcpcd.service failing to start? Worked with 24.05?

dhcpcd.service: Failed to set up mount namespacing: /proc/sys/net/ipv6: No such file or directory
dhcpcd.service: Failed at step NAMESPACE spawning ... No such file or directory

Seems to fail with

boot.kernelParams = ["ipv6.disable=1"];

Also there is #355450.