ADG5412 NC 12PIN issue

We have a customer when use ADG5412 design wrong, they connect PIN12 NC to 5Vcc, this made PIN12 damage occasionally. now ADG5412 is MP, they need to know PIN12 NC  internal block,if PIN12 is open or have other electrical connection for function testing ?  ADG5412's datasheet  do not  have PIN12's information or bolck, so looking forward to your reply, thanks!