I know I know I should use the quick-gen API in the future. But existing software uses the batch keygen api.
The problem here is that the behavior is different regarding the expiry date. For quick-gen / gen key with gnupg we have a default expiry. And then For batch keygen we don't. Example:
key-type: RSA key-length: 2048 key-usage: sign,encrypt name-real: expiry-test
Generates a key without expiry.
This leads to Kleopatra / KMail generating keys without expiry dates by default and has been reported as a bug there.