The document contains that following (hitherto unnumbered) issue:

In the example output above we see Turtle's shorthand syntax for dealing with blank nodes. Should the recommended output form explicitly identify the blank nodes using the row number? e.g.

csvw:row _:1 , _:2 , _:3 , _:4 .

_:1 :country "AD" ; :name "Andorra" .

etc.

However, I think this can be only a MAY or possibly (but reluctantly) a SHOULD. Indeed, if an implementation relies on an external RDF package, leaving the serialization done by that package, then there may be no control over the identifier used for blank nodes. Ie, this requirement cannot be reinforces in such a setup.