Currently there is no standard for version/natural sort ordering.
That is: there is no one correct way or universally agreed-upon way to order items. Each program and each programming language can decide its own ordering algorithm and call it ’natural sort’ (or other various names).
See Other version/natural sort implementations for many examples of differing sorting possibilities, each with its own rules and variations.
If you do suspect a bug in coreutils’ implementation of version-sort, see Reporting bugs or incorrect results on how to report them.