Certbot: 0.9.1 fails in non-interactive use (pythondialog, error opening terminal)

Debian8 auto-updated box using the auto-updating script, I have a shell script + cronjob to update my cert @weekly
Oct 02 it ran successfully, Oct 09 it updated 0.8.1 -> 0.9.1 and died.

Upgrading certbot-auto 0.8.1 to 0.9.1...
Replacing certbot-auto...
Creating virtual environment...
Installing Python packages...
Installation succeeded.
An unexpected error occurred:
Bug in pythondialog: expected an empty output from u'infobox', but got: u'Error opening terminal: unknown.\n'Please see the logfile 'certbot.log' for more details.

Logfile output:

2016-10-15 21:01:18,381:DEBUG:certbot.main:Root logging level set at 20
2016-10-15 21:01:18,420:DEBUG:certbot.main:Exiting abnormally:
Traceback (most recent call last):
  File "/root/.local/share/letsencrypt/bin/letsencrypt", line 11, in <module>
    sys.exit(main())
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/certbot/main.py", line 749, in main
    setup_logging(config)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/certbot/main.py", line 653, in setup_logging
    logger.info("Saving debug log to %s", log_file_path)
  File "/usr/lib/python2.7/logging/__init__.py", line 1160, in info
    self._log(INFO, msg, args, **kwargs)
  File "/usr/lib/python2.7/logging/__init__.py", line 1279, in _log
    self.handle(record)
  File "/usr/lib/python2.7/logging/__init__.py", line 1289, in handle
    self.callHandlers(record)
  File "/usr/lib/python2.7/logging/__init__.py", line 1329, in callHandlers
    hdlr.handle(record)
  File "/usr/lib/python2.7/logging/__init__.py", line 757, in handle
    self.emit(record)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/certbot/log.py", line 64, in emit
    self.width + self.PADDING_WIDTH)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/dialog.py", line 2675, in infobox
    kwargs)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/dialog.py", line 1765, in _widget_with_no_output
    widget_name, output))
PythonDialogBug

My main box is using the Debian-shipped binary package (0.8.1), so that's still functional, but my home box got hit, since I implemented it earlier (before Debian provided the package) - I imagine other users are probably also afflicted, but they might not have noticed. I certainly didn't for over a week.

Shell script in question:

#!/bin/sh
/letsencrypt/letsencrypt-auto certonly --webroot --renew-by-default -w /var/www/git-ssl-proof/ -d git.nikomo.eu
systemctl reload nginx

I'm too lazy to fix the problem for real, so I'm just going to switch to the Debian package, but I reckon other people might also get bit by this.