Storing single address in the SA.

There seems to be some confusion in the design draft regarding the single address storage
in the SA. 

In section 5.2.1,

   The single IP address approach will not work if both peers happen to
   loose their IP address at the same time (due to, say, the failure of
   one of the links that both nodes are connected to).

I can understand this. 

But In section 5.3,

   Note that if only a single address is stored in the peer address set
   (instead of an address list) we might end up in the case where it
   seems that both peers changed their addresses at the same time.  This
   is something that the protocol must deal with.

What does this mean ? Could someone clarify ?

-thanks
mohan