Currently the I18n::Backend::Gettext module treats "context" (in pgettext and npgettext) and "scope" in almost the same way. Basically, it expects the context to be in the "Context|Real translation text" format. They are totally different though in Gettext : http://www.gnu.org/software/gettext/manual/gettext.html and the context is implemented through the msgctxt key in the PO file.
I know that this is not currently supported in the i18n API so I'm sure whether this could actually be supported but then it could be better to raise a warning at least that the two functions (pgettext and npgettext) are being used.
Please see the pull request for failing test proof + fix. My apologies for the stupid fixture names in the po (couldn't think of anything better)
Failing test for npgettext with msgcntxt. Refs #116.
Fix #116 (npgettext with msgcntxt).
Issue #116 Expose as a gem