When importing a CA hierarchy with Configdump, the issuer must be imported before the subject, but this order is not enforced. Thus you may end up with the error:
The solution is to manually import the issuer before the subject by running Configdump twice.
Configdump should do dependency resolution during import to ensure that the order in the YAML file does not matter. Write utility class which reorders a list of CAs. It should work both for the trivial CA hierarchy Root -> Sub CA, but also for more complex CA hierarchies with multiple levels, cross-signings ect.