GroupMemberCountExceedsAllowedLimit error while adding a AAD SG on powerbi workspace

I have been trying to add one AAD "Security" Group as a "viewer" to my Power BI workspace linked to "Embedded Capacity (A1)" but its keep on failing with below error i.e. GroupMemberCountExceedsAllowedLimit, As per error message looks its due to limit on total number of members in SG but I've even tried removing all users from SG (empty SG) but the error still persists, Tried adding SG manually as well as using PBI Rest API but no luck. Any leads are highly appreciated..