Also, for Return All and Return Mapped, etc (just about anywhere where is the possibility to select attributes) the user must have the option type anything or add anything to the list.
This was due to some bad logic on adding and remove SAML options from the list when the client type changed. A fix has been pushed into the mgmt-domain-regex branch
The attribute release policy section only shows 3 policies, and the default selection seems to be "Policy"
Other options are missing that would be: Return Allowed, Return All, Deny, etc https://apereo.github.io/cas/development/integration/Attribute-Release-Policies.html
Also, for Return All and Return Mapped, etc (just about anywhere where is the possibility to select attributes) the user must have the option type anything or add anything to the list.