CiviEvent Fees not displaying

Using Drupal 7.7.1/Civi 5.26.1 I’ve set up a paid event with two price options (Waged/Unwaged), with no ‘Pay Later’ and Stripe as payment processor.

When I use the registration page for this event (test or live) in a logged in browser, the prices display OK and registration succeeds, but the prices don’t display on the live registration page for a browser that is not logged in. All the other elements on the page seem fine.

Anonymous users’ permissions to ‘register for events’ and ‘view events’ are set.

Log messages are

Warning: array_intersect_key(): Expected parameter 1 to be an array, null given in CRM_Event_Form_Registration->buildCustom() (line 550 of /var/www/clients/client4/web5/web/sites/all/modules/civicrm/CRM/Event/Form/Registration.php)

and

Notice: Undefined variable: fields in CRM_Event_Form_Registration->buildCustom() (line 550 of /var/www/clients/client4/web5/web/sites/all/modules/civicrm/CRM/Event/Form/Registration.php)

I see in Registration.php @550 that this error may(?) relate to profile fields, but these seem to be displaying & filling OK.

Advice gratefully received.