Path is undefined error even though a path is defined - then route filter error

Drupal 9.5.1
PHP 8.1.11

To reproduce, just set a path in a data export display. The "path undefined" error will appear. If you save the view anyway, then try to load in a browser window, you'll get a "client error." Here's the error in the log:
Symfony\Component\HttpKernel\Exception\NotAcceptableHttpException: No route found for the specified format html. Supported formats: csv, json, xml. in Drupal\Core\Routing\RequestFormatRouteFilter->filter() (line 65 of /code/web/core/lib/Drupal/Core/Routing/RequestFormatRouteFilter.php).