Proposed resolution:

This wording is relative to N5046.

1. Modify [hive.operations] as indicated:

   template<class Compare = less<T>>
     void sort(Compare comp = Compare());
   

   -13- Preconditions: `T` is Cpp17MoveInsertable into `hive`, Cpp17MoveConstructible, Cpp17MoveAssignable, and Cpp17Swappable.

   -14- Effects: Sorts `*this` according to the `comp` function object. If an exception is thrown, the order of the elements in `*this` is unspecified.

   […]

`std::hive::sort` ([hive.operations]) requires that `T` be Cpp17MoveInsertable into `hive`, Cpp17MoveAssignable, and Cpp17Swappable. It does not require `T` to be Cpp17MoveConstructible, which is a prerequisite for the internal use of `std::sort` by the implementation. Note that, in general, Cpp17MoveInsertable into `hive` (or any container) does not imply Cpp17MoveConstructible. Both the de facto reference implementation for `std::hive` (Matthew Bentley's plf::hive) and the ongoing implementation for VS use `std::sort` directly on `T`.

Strictly speaking, the lack of this precondition can be salvaged by invoking `std::sort` on a range of values of type `X`, where `X` is an ad-hoc type wrapping a `T` value and an allocator object which implements move construction in terms of std::allocator_traits<A>::construct. So, even if this issue is resolved as NAD, that would be informative for standard library implementors so that they can potentially fix their code.