keybase follow fails with "Failed to parse public key at position 1" for a particular user

I'm trying to `keybase follow superboum` but it fails with
```
▶ NOTICE Failed to parse public key at position 1
▶ ERROR Bad key family: No key found for XXXXXXX
```

I tried following somebody else and it worked. Is there something wrong with keybase or with this user?

I'm using the current keybase binary on macOS, I tried both with the one for the application and with the one from homebrew.

Start by reproducing `keybase follow superboum` on macOS with both the application and Homebrew binaries, then compare the result with following a user that works. Trace the reported public-key parsing and key-family errors; done means identifying whether the failure is user-specific or a client defect and recording a confirmed resolution.

Written by the indexing model from the issue text.