Issues with Contextual Search on Service Portal for users who have "snc_external" role
London patch 6
1) The root cause of this issue is the explicit roles on REST APIs
2) It is calling table level API (screenshot attached) which responds with 403 error as external user is not authorized to call table level APIs.
PRB1323751 was created to address the issue and fix was targeted for Madrid Patch 4 & New York releases