You are getting the below error when clicking into a custom attribute "Additional Project Managers" in the New User Experience (UX)
Error: "One or more parameters 'param_proj_id' are not API-enabled. You may see unexpected results."
The associated lookup isn't parameterized and there is nothing showing in the logs for the issue.
This can happen if the associated lookup was parameterized and then later updated to NOT be parameterized, but the parameters stayed in the odf_lookup_parameters table.
Check to see if the attribute shows up in the odf_lookup_parameters table by running the below query:
select * from odf_lookup_parameters
where object_code = 'project'
Release : Clarity 16.0 and lower
The root cause is fixed for this issue in 16.0.1 as part of Changing a parameterized lookup via XOG to non-parameterized breaks the attribute in the MUX
Workaround: Contact Broadcom support for assistance.