We can't do anything about it.
Cards with manufacturer id 5 and serial numbers up to 346 (0x15a) are affected.
Newer cards work fine.

Done in trunk (2.1), rev 5233

This is now a known problem. The likely reason is bug in the card's code. The
workaround is to forget about card based 3072 bit encryption keys.

Does the fact that I can encrypt, sign, and authenticate correctly with 3072 bit
keys affect your hypothesis?

According to http://pcsclite.alioth.debian.org/shouldwork.html#0x0B970x7762
this reader should work but it has not been tested.

Is there any more information I can provide? Can you reproduce it?

This is the built-in reader in my Dell Latitude D430, by the way.

This is the relevant lsusb output:

What card reader are you using?

Closing this report. If further support is required, please reopen.

Note: It also works for gpgme_op_decrypt_verify, but the error code
GPG_ERR_NO_DATA needs to be ignored in this case. This is because we didn't get
a DECRYPTION_OKAY status message, and this is semantically the same as for a
signed but not decrypted file. We can consider making this case better in a
major upgrade when we change the ABI anyway, but not now.

Works fine for me with gpgme_op_verify, which actually runs the gpgme -o command
as you gave it. Did you rewind the output data object before trying to
read the data?

Marcus: Can you please check whether we can easily add this to gpgme_op_decrypt?

Background info: My e-mail program is currently calling gpg via fork() and
exec() and is thus very GnuPG version dependent. It does not create such
messages, but can display them. Trying to get rid of the version dependency,
I've tried to switch to GPGME and stumbled about a test message I've received
years ago. Unfortunately the header lines do not mention what mail program was
used for sending.

I was not aware that such OpenPGP messages are actually used. We need to see how
to implement that.

Similar to T780 I guess.

Integrated into 2.0.

Fixed in 1.4 (r4445). I haven't integrated the fix to 2.0 yet.

David, I know you investigated this bug. What is the current status?

I don't have an immediate answer to this. Need to fire up the debugger.