net-wireless/crda-1.0.1-r1 installs udev rules in /lib64/udev/rules.d/85-regulatory.rules. sys-fs/udev-124-r1 (latest stable) only looks for rules in /etc/udev/rules.d -- support for /lib64/udev/rules.d was added in udev-125. This stops crda from working.
UDEV maintainers, could we have 135 stable as per bug #254616 please, failing that, how about 125 for now?
I don't really care if you want udev-125-r2 stable, it should be ok. But then someone needs to check which already fixed bugs need the fixes downgraded to that version.
Assuming AMD64 based on your /lib64 path (do post emerge --info next time to take the guesswork out of it please); a newer udev has since gone stable which fixed this unfortunate bug.
My problem is indeed fixed (and I do use amd64, as selected in the Hardware field), thanks! But the bug does not seem to be architecture-specific, so it probably still occurs on ppc and ppc64.