cachet: Missing argument 1 for Illuminate\Support\Manager::createDriver()

I get the following error when adding a new incident:

production.ERROR: exception 'ErrorException' with message 'Missing argument 1 for Illuminate\Support\Manager::createDriver(), called in /var/www/virtual/rnet/cachet/bootstrap/cache/compiled.php on li
ne 12040 and defined' in /var/www/virtual/rnet/cachet/bootstrap/cache/compiled.php:12034

Relevant lines in /var/www/virtual/rnet/cachet/bootstrap/cache/compiled.php:

protected function createDriver($driver)
{
    $method = 'create' . ucfirst($driver) . 'Driver';
    if (isset($this->customCreators[$driver])) {
        return $this->callCustomCreator($driver);
    } elseif (method_exists($this, $method)) {
        return $this->{$method}();
    }
    throw new InvalidArgumentException("Driver [{$driver}] not supported.");
}

The error results in an error 500 page, but the incident gets created and is editable/removable as normal.