Hi,
at the current state it seems to be impossible to use the same private (sub)key
on multiple smart cards as the created stub is bound to the serial number of the
smart card.
A workaround for the moment is to delete the according private stub every time I
change smart card or change from smart card to yubi key but this would make a
great feature.
Also, deleting a secret key stub from gnupg using " gpg2 --delete-secret-key"
does NOT remove the stub from gpg-agent - the according file in
~/.gnupg/private-keys-v1.d/ has to be deleted manually.
Should I file a second bug report/feature request for that?