[range.split.outer] p1 says:

Many of the following specifications refer to the notional member current of outer-iterator.
current is equivalent to current_­ if V models forward_­range, and parent_­->current_­ otherwise.

It's unclear which following specifications that means. Does that only apply to the rest of [range.split.outer]? Presumably not, because the next subclause, [range.split.inner], also refers to current.

I think it should be made clear that it applies to the whole of [range.split].