Hi @Pankhuri,
I know this feature update may have happened prior to when you started encountering issues but I wonder if this has something to do with it as this rollout happened earlier this year:
Based on what you mentioned above though, regarding the two ways you’ve been able to resolve; both of those seem to include the removal of RLS rules so the issue must be occurring in how the permissions are being handled.
If nothing has been changed on your dataset or your RLS dataset, then I would suggest creating a support ticket so that you can get more personalized account assistance from the AWS support team.