Unfortunately the commit
https://git.gnupg.org/cgi-bin/gitweb.cgi?
p=gnupg.git;a=commitdiff;h=1c09def22d97de3738a2bec4970504bfc155680b
got not backported to the stable 2.0 branch, see
https://lists.gnupg.org/pipermail/gnupg-devel/2014-September/028759.html
for details.
My symptom is like follows:
$ gpg-connect-agent
SIGKEY 44A7BBB8FD7AEBB001E0DA06A0A892EFC341C71E
OK
SETHASH 8 79E12A66EFAAD785A443BB9787C8EF8A87F0DF4AA9669C452FCEBC67D323C42B
OK
PKSIGN
ERR 100663351 Invalid value <SCD>
Please backport the SHA-2 fix to gnupg-2.0 now that SHA-1 is deprecated for 6 years.
TIA, Wolfgang