I am not the original reporter. I just saw that Pull Request on GitHub:

Quote:
In the case that a system is booted diskless with NFS root, such as in a cluster I am building, then the OpenRC default behavior crashes the system. A new 'subsume_bond<x>="<kernel-autoconfigured-iface>"' option in /etc/conf.d/net is implemented to resolve the issue, and a warning is added where bonding is used on systems with root on NFS in order to advertise the solution.

Related to: https://bugs.gentoo.org/show_bug.cgi?id=428604

If you close this bug, you should also do something with the pull request:
https://github.com/funtoo/openrc/pull/1