Merging 2 records with Drupal accounts results in 2 Drupal accounts with the same email

Steps to recreate:

1. create two Drupal users with different emails
2. create a civiCRM record for both users, with an identical first name and last name
3. use the Fuzzy individual rule to match on first/last name
4. merge these Contacts
5. the result is that two Drupal accounts with the same email address now exist, neither Drupal account is deleted or blocked. This creates login problems