OK ... I have more and thought it odd. My season salt does the same thing - starts reddish then gets real pale.
In the UK the pink salt (which often isn't pink) is shipped with a best before date of 12 months. With such a long date (which is only advisory) providing it had been kept dry and sealed I would be happy using it up to about 18 months. As aeroforce100 says - it isn't expensive so why would you take the risk?
It may be safe, but I would just get some more. It is very inexpensive.