keybase fails to upgrade via apt

The package remains as partially installed, and keybase services are restarted with each apt run.

> dpkg: error processing keybase package (--configure):
> subprocess installed keybase package post-installation script returned error exit code 1.

However, the application seems to update and launches correctly.
The `/keybase` mount folder becomes corrupted?

```bash
$ ls -alh / | grep keybase
ls: can't access 'keybase': The other end of the connection is not connected
d????????? ? ? ? ? ? keybase
```

Keybase version: 5.9.0-20220120174718+95a3939b3a
OS: Linux Mint 19.3

Start by reproducing the apt upgrade on Linux Mint 19.3 and inspect the dpkg post-installation error alongside the corrupted /keybase mount state. Trace why the keybase services restart during apt runs; done means the package configures successfully, the mount remains usable, and repeated apt runs do not restart the services unnecessarily.

Written by the indexing model from the issue text.