This morning, I updated my dev sites from CiviCRM 5.25 to 5.34 and since then, I have found that Drupal accounts are not being created when a member signs up in CiviCRM.
We have a page for signing up for a membership, here - https://civi.artspan.org/civicrm/contribute/transact?reset=1&id=3
On the live site, if someone fills out this form, a Drupal account is created for them and they are automatically logged in. On the dev site, only a CiviCRM account is being created.
Nothing has changed between these two sites except for the CiviCRM update.
Under the profile settings for that form, "Drupal user account registration option? is marked as "account creation required".