Noticed this while working on T3579 for kleopatra. For secret keys I don't get the uid signatures. I added display of user id signatures to gpgme's run-keylist with
5ba1cbdf39efd90c7987bfc2bc030b6504e70076
./run-keylist --secret --sigs 1FDF723CF462B6B1
does not show signatures
./run-keylist --sigs 1FDF723CF462B6B1
Shows them.