We have an integration the uses an Apex Webservice to allow a backend system to access support information, including chats and cases. When we built it in a sandbox several months ago, we decided to use the new, free "Salesforce API Only System Integration" License type. We used a permission set to grant access to the Apex webservice class, and we used another permission set to grant CRUD and FLS on a few objects, including Case, as outlined in this answer. Note also the comments on that answer, one of which was from me, based on the work we did in the sandbox.
Now I'm trying to deploy this solution, and I cannot assign the object-access permission set to a user with the Integration license. I'm getting an error,
The user license doesn't allow the permission: View All Cases
However, I was able to assign the same permission set to a user with the same license in the sandbox. It's the identical permission set, as it was changesetted from sandbox to prod. Has something changed? I can't find any documentation about such a change.
I also tried creating a new Permset and assigning it to the specific License type; in that case the Case object just isn't available in the permset editor.