Is a custom time-varying (TSV) attribute available in the Modern User Experience (UX)?
Release : 15.9.2 and lower
In 15.9.2 and lower, the custom time-varying attributes are not available in the modern UX. When this type of attribute is created it does not have an API Alias field. If there is no API Alias it will not be available in MUX.
As per documentation at Add Project Fields to a Blueprint:
Adding the API Attribute ID to the following attribute types in Classic PPM Studio is not supported. You cannot configure these attribute data types to appear on the blueprints Fields list:
This functionality for Custom time-scaled value (TSV) attributes is now available. See more details on this change at: Introducing Custom TSVs in Clarity
Refer to Getting Started with Clarity (15.9.0)