Is this a "reportable" bug?

What counts as a reportable bug in Crux and what is "upstream" and therefore someone else's responsibility? I ask because there is a critical bug in Sylpheed v.310 (built last week) which seems to be identical to one reported on the Debian list on 2nd February (Bug #611855). -- Hazel Russman <hazel_russman@yahoo.co.uk>