Calling REST API to create/update data assignment for some users gives an error

Summary:

Calling the /fscmRestApi/resources/11.13.18.05/dataSecurities (POST/PATCH) Rest API gives this error for some users -

Applying List binding LOV_UserName with given set of values leads to multiple matching rows for a row of type:UserRoleDataAsgnmnts1, key oracle.jbo.Key[ 300000005195512]

Content (please ensure you mask any confidential information):

Hello team,

• I am creating users, assigning roles and data assignment using the Fusion REST APIs for a use case.
• I've executed the same process for 2 users so far - let's call them A and B. I created the users, assigned roles to them and then proceeded with data security assignments in the same way.