At ~1:45PM EDT on Aug 8, 2022, API 4.133.0 was released into production. This release included a change to the way grants were configured to ensure they were not overly broad for security reasons. In the process, this prevented customers from being able to access opened tickets that had already received a response from Support.
Support was able to identify this issue as customers reported it via phones and newly created tickets then escalated the issue to the administrators. A hotfix to address the issue securely was released at ~6:32PM EDT which allowed customers full access to their Support tickets once more.
Additional testing will be implemented for future API releases to ensure this issue does not happen again.