Comment 1 for bug 2011298

As you mention, this is by design and I'm not sure there's an easy path to change this due to backwards compatibility issues. In general, it shouldn't be necessary to have multiple network configs, and there's not enough information in your example for me to understand the use case.

Is it possible to provide a more concrete example? Can you attach the arguments being provided on the kernel cli along with the 50-cloud-init.yml you're manually generating, or any other config you want applied?