After reinstall, operations fail with "No secret key available"

I was getting started with Keybase on my Ubuntu laptop, and here's what I did:

• Briefly attempted to install the node client before I read it was deprecated; hit Ctrl-C halfway through.
• Installed the Go client via the deb package (curl | sudo dpkg -i).
• Attempted keybase login, but it failed with a permission error. I found that ~/.config/keybase was owned by root. chown -R mquander:mquander (myself) fixed it.
• Made a few proofs.
• In an attempt to reproduce the permissions problem, I uninstalled the package and deleted ~/.config/keybase. Then I reinstalled the package (the permissions problem didn't reproduce -- it was owned by mquander this time) and did keybase login again. This time keybase login did not ask me to provision the device; it just took my keybase passphrase.

Afterward, signing and other operations failed due to the error provided in the title. I saw https://github.com/keybase/client/issues/1411 and ran keybase pgp select --only-import to import my key again. That worked, and I can sign, encrypt, and decrypt messages. However, other operations still fail:

crescens:~$ keybase prove hackernews mquander
You already have a proof for mquander@hackernews; overwrite? [y/N] y
▶ ERROR No secret key available

crescens:~$ keybase deprovision

mquander, BE CAREFUL!  \('o')/

You are about to delete this device from your account, including its secret
keys. If you don't have any other devices, you'll lose access to your account
and all your data!

Also, the secret keyring you're about to delete contains PGP keys. To list them
or copy them, use `keybase pgp export`.

Proceed? (type 'YES' to confirm): YES
▶ INFO Revoking KIDs:
▶ INFO   01200798af7c953d8be52d1579cfc05e09e458aa31eeb76823eeef10c7e66e74b0d30a
▶ INFO   0121da1190f11b0a43310ff69f63758fb427e518cd6c612eda626997b296278c22730a
▶ ERROR No secret key available

Reproduce the reinstall and login sequence, then run the mentioned keybase prove and keybase deprovision commands after keybase pgp select --only-import. Trace the login/provisioning and secret-key handling entry points implicated by the failure; done means these operations no longer report "No secret key available."