One of our users has different options between the classic UI and the Modern UX. When he navigates to the Task tab of a project in the classic UI, under the Open in Scheduler he had both options for MSP Read-Write and Read-Only.
But in the Modern UX, he has options for Workbench.
Release : 15.8.1
Component : CA PPM MICROSOFT PROJECT (MSP)
This issue is due to the field being secured in Modern UX, and the user not having rights to the secured field.
The field can be configured to not be secure, or the user can be granted "view" rights to the secure field in Modern UX.