Rule 11.3 - Unclear Example 3

[thohae]

The third and last example of Rule 11.3 states that

Code:

int * const * pcpi;
const int * const * pcpci;
pcpci = ( const int * const * ) pcpi;

is non-compliant because the unqualified pointer types are different, namely “pointer to const-qualified int” and “pointer to int”

But the rule's amplification explicitly states, that

This rule applies to the unqualified types that are pointed to by the pointers.

and that the rule's goal is to prevent misalignment.
I do not understand why the example is non-compliant, as the cast only adds a const-qualifier and leaves the base type as it is (i.e. "int").
Could you please explain this a little further?