Hi, when Toolset Access is active and managing a CPT, Authors cannot see CPT custom fields in the backend. Administrator can see them correctly when editing any post of the CPT, but Authors cannot edit the custom fields of their own post in the backend. If I deactivate Access they can see the custom fields.
Here is the test site where you can login using the following link:
=> hidden link
I've created two authors and I've set "user-author1" as author of the post "Boxing Training" belongs to "Session":
=> hidden link
You can login to "user-author1" using password Admin@999 and you will notice you will be able to Edit post "Boxing Training" and you can see and edit the custom fields as well.