Admin RestAPI Create Group with clientRoles

Greetings everyone,

I am trying to create a group with admin restapi by providing clientRoles on payload,
like this:

{ "name": "groupExample", "clientRoles": { "frontend": ["_customer-service"] } }

and tried like this:

{ "name": "groupExample2", "clientRoles": { "4da723e5-b49c-4a33-bb40-3fddd6bfa117": ["_customer-service"] } }

and also tried various combination like passing role ID instead of name,
none of the attempts resulted to map the client role to the group.

The group itself is created successfully but roles are not mapped.