Generally, this situation will not happpen. However, in rare scenarios, it will only happen in case of two users trying to join simultaneously and there is no room on server but the 3rd user will always get room to join.
To permanentaly avoid this situation, once this scenario happen, you can check for the rooms available with 1 user on server using our getRoom API. If there is room available to join then you can leave the current room and join that room.
Please let me know if you have any other queries.