gpg --decrypt something.gpg # this works
gpg2 --decrypt something.gpg # this fails

gpg --list-secret-keys # reads from ~/.gnupg/secring.gpg
gpg2 --list-secret-keys # reads from ~/.gnupg/pubring.gpg (pubring?!)

/home/<username>/.gnupg/pubring.gpg
---------------------------------
sec   rsa4096/AAAAAAAA <date> [SC]
uid         [ultimate] <description of me>
ssb   rsa4096/BBBBBBBB <date> [E]

> keyinfo --list
S KEYINFO <keygrip associated with AAAAAAAA> D - - - P - - -
S KEYINFO <keygrip associated with BBBBBBBB> D - - - P - - -
OK

gpg: using PGP trust model
gpg: using subkey BBBBBBBB instead of primary key AAAAAAAA
gpg: This key belongs to us
gpg: reading from 'testfile'
gpg: writing to 'testfile.gpg'
gpg: RSA/AES256 encrypted for: "BBBBBBBB <description of me>"

gpg: public key is BBBBBBBB
gpg: using subkey BBBBBBBB instead of primary key AAAAAAAA
gpg: using subkey BBBBBBBB instead of primary key AAAAAAAA
gpg: encrypted with 4096-bit RSA key, ID BBBBBBBB, created <date>
      "<description of me>"
gpg: public key decryption failed: Operation cancelled
gpg: decryption failed: No secret key

gpg2 --import ~/.gnupg/secring.gpg

gpg --gen-key

gpg --gen-key