Frank Ellermann wrote nonsense, see also
<http://permalink.gmane.org/gmane.ietf.rfc822/12049>
What Alexey found is an ordinary 2821 bug, no 2822 issue.
2822 + 2822upd have:
| quoted-string = [CFWS]
| DQUOTE *([FWS] qcontent) [FWS] DQUOTE
| [CFWS]
2821 + 2821bis have:
| Quoted-string = DQUOTE *qcontent DQUOTE
The "bare SP" case is AWOL, and 2821bis can simply add it:
Quoted-string = DQUOTE *(SP / qcontent) DQUOTE
John's proposal <qcontentSMTP> does this, eliminating all
undesired 2822upd-obs cases (roughly 2822-obs + NO-WS-CTL)
Frank
--
@ Alexey, if you need the missing SP *now* (in RFC 2821)
maybe submit it as 2821 erratum. Or wait for 2821bis.