Otherwise, if T is an enumeration with a fixed underlying type ([dcl.enum]) U, the initializer-list has a single element v, v can be implicitly converted to U, and the initialization is direct-list-initialization, the object is initialized with the value T(v)

v cannot be implicitly converted to U at all, since the following rule

An expression E can be implicitly converted to a type T if and only if the declaration T t=E; is well-formed, for some invented temporary variable t

enum A:int{
   a = 0
};
A a = 0; // ill-formed

There's no implicitly conversion that can convert 0 to type A. The relevant modification is suggested by CWG2374. However, its intent is:

v can be implicitly converted to the underlying type of T

So, Does it the current wording make no sense?