I’m working with linux gnuPG. It looks like at some point I received a public key without a UID. I’ve since receaved a new key, with uid, but the original key can not be deleted from the chain. Further more when trying to restore keys from a backup it fails at this key.

$ gpg --list-keys D7FA4AC2
gpg (GnuPG) 2.0.22; Copyright ...

Fatal error: Invalid argument
Aborted

$gpg --list-keys --keyid-format long D7FAC2
pub   2048/83191D...
uid
sub   2048R/E1387...

$gpg --delete-key 83191D...
gpg (GnuPG) 2.0.22; Copyright ...

Fatal error: Invalid argument
Aborted