After upgrade to 5.48.0 Error: Mailing cannot be sent. There are missing or invalid fields (subject,name,from_name,from_email,body).
After upgrading from CiviCRM 5.47.2 to 5.48.0, any attempted mailing creates an error after clicking "Submit Mailing" with "Mailing cannot be sent. There are missing or invalid fields (subject,name,from_name,from_email,body)." Those fields are clearly filled in in the mailing, and when submitting a test mailing, it goes through, and the test mailing is sent and delivered.
I'm on Drupal 7. Using CiviMail with Mosaico.