There a couple of mailing list where the project lives. For historical reason they are based on the original pkg-grass project area on Alioth
In the past instead of debian-gis the pkg-grass-general list was used for which there still is a Gmane Archive.
The developer list is send-if-subscribed-only kind of list, in order to minimize the spamming forwarded to subscribers. That can introduce a little delay in email delivery, of course for non-subscribed people. Just in case, don't send twice messages: the lists admin will accept them in as soon as possible (consider the GMT+1 time zone too).