Unable to decrypt with PGP on Yubikey

sops -v
sops 3.10.2 (latest)

gpg --version
gpg (GnuPG) 2.4.8
libgcrypt 1.11.2
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License GNU GPL-3.0-or-later <https://gnu.org/licenses/gpl.html>
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There is NO WARRANTY, to the extent permitted by law.

I have an OpenPGP key on my yubikey smart card, which I can use to decrypt. e.g. this works:

gpg -d foo.gpg

But when calling sops, an error occurs

sops -d bar

Output:

Failed to get the data key required to decrypt the SOPS file.

Group 0: FAILED
  xxxx: FAILED
    - | could not decrypt data key with PGP key:
      | github.com/ProtonMail/go-crypto/openpgp error: could not
      | load secring: open /Users/fzakfeld/.gnupg/pubring.gpg: no
      | such file or directory; GnuPG binary error: failed to
      | decrypt sops data key with pgp: gpg: encrypted with RSA key,
      | ID xxxx
      | gpg: using "xxxx" as
      | default secret key for signing
      | gpg: public key decryption failed: No secret key
      | gpg: decryption failed: No secret key

How can I debug this further? Reading https://github.com/getsops/sops/issues/189 it seems like gpg2 is supported and sops is trying out the gpg binary

Reproduce the failure with sops -d bar and compare it with the working gpg -d foo.gpg command, using the reported sops 3.10.2 and GnuPG 2.4.8 versions. Investigate how sops invokes GnuPG for PGP decryption and how that interacts with the Yubikey-backed secret key. Done means identifying the cause and providing a verified fix or clear debugging guidance.