When DHCP (dhcpcd in my case) is started, wrapper in /lib/rcscripts/net.modules.d/helpers.d/ is used. This wrapper loads module-loader, which tries to source only `/etc/conf.d/net'. The problem is that the configuration can stay entirely in `/etc/conf.d/net.{interface}', so it should be sourced also. And this is currently my problem. Order of sourcing should be - according to runscript.sh - `net.{interface}' first and then `net' (if I'm right). But this is questionable as the postup() functions do not have any specialization (like postup_{interface}() function).
I created a separate bug #118368 for the postup_{interface}/order of sourcing thing.
Fixed in our svn repo - will be in baselayout-1.12.0_pre14
baselayout-1.12.0_pre14 is out