When attempting to create a risk in the new UX, an 'Error creating instance' error is thrown. The logs also contain an error similar to the following:
ERROR 2019-07-01 11:14:26,112 [http-nio-14001-exec-95] rest.validation (clarity:admin:12345678__123D4CD0-1234-123B-1EC2-C12D12345F12:PPM_REST_API) ExceptionInfo :: Could not create resource. Resource name: risks. Error code: validation.lookupValueInvalid Error message: CMN-0009: Attribute ''aaaaa' has invalid Lookup Value 'bbbb'
Release : 15.6.1
Component : CA PPM STUDIO
This error will occur if there is a default set on a lookup attribute on the Risk object, and then this value is deactivated on the lookup. Once the value gets deactivated, it will no longer show as the default on the attribute in the UI (under the risk object), but once a new risk instance is attempted to be created, this default will be used. This then causes the error.
Once the default is cleared from the attribute on the risk object (by going to Administration - Objects - Risk - Attributes - opening the attribute, and clicking on the grey 'x' on the default field), the error will no longer occur.