[expr.const.cast] p3 states

For two similar types T1 and T2, a prvalue of type T1 may be explicitly converted to the type T2 using a const_­cast if, considering the qualification-decompositions of both types, each P¹_i is the same as P² _i for all i. The result of a const_­cast refers to the original entity.

Presumably, the requirement in this rule should impose on any case that uses the const_cast casting. Even though the conversion would be a standard qualification conversion, it is not supported

typedef int CK[][2];
int main(){
   int arr[2][2]; 
   CK& rf0 = arr;  // ok, qualification conversion 
   CK& rf = const_cast<CK&>(arr);  // ill-formed, the requirement is not satisfied
}

Change [expr.const.cast] p3 to

For any casting from an expression of type T1 to type T2 using a const_cast, considering the qualification-decompositions of both types, each P¹_i shall be the same as P² _i for all i. The result of a const_­cast refers to the original entity.

The rules defined in the subsequence paragraphs that use const_cast casting all should satisfy this precondition.

Another issue appears in [expr.const.cast] p7: U1 suddenly appears without any introduction. Maybe, change it to

A conversion from a type T1 to a type T2 casts away constness if T1 and T2 are different, there is a qualification-decomposition ([conv.qual]) of T1

cv¹₀ P¹₀ cv¹₁ P¹₁ ... cv¹_n-1 P¹_n-1 cv¹_n U₁

yielding n such that T2 has a qualification-decomposition of the form

cv²₀ P²₀ cv²₁ P²₁ ... cv²_n-1 P²_n-1 cv²_n U₂

and there is no qualification conversion that converts T1 to

cv²₀ P¹₀ cv²₁ P¹₁ ... cv²_n-1 P¹_n-1 cv²_n U₁

would be more clear.