This has been reported by a Debian user and it is to my opinion a bug. The
output of --fingerprint <keyid> and --with-fingerprint <keyfile> are slightly
different. Using the reporters example:
% gpg --with-fingerprint AC15B50C.asc
pub 1024D/AC15B50C 2004-12-26 Evgeni -SargentD- Golov <sargentd@die-welt.net>
Key fingerprint = 0C04 F872 0963 ADC9 AA83 882B 24A0 1418 AC15 B50C
uid Evgeni Golov <evgeni@golov.eu>
[..]
% gpg --fingerprint AC15B50C
pub 1024D/AC15B50C 2004-12-26
Key fingerprint = 0C04 F872 0963 ADC9 AA83 882B 24A0 1418 AC15 B50C
uid Evgeni -SargentD- Golov <sargentd@die-welt.net>
uid Evgeni Golov <evgeni@golov.eu>
[..]
In the first case the first UID is above the fingerprint. This seems to cause
issues with gpgsigs.