Patches sent to the meta OE mailing list are appropriately displayed in Patchwork (http://patchwork.openembedded.org/project/oe/list/) but after some time between a few hours to a couple of days they get archived and are no longer available. This behavior is not present in all Patchwork's project lists (for example, OE-Core).
It's not bug, it's what I do to maintain the patches on patchwork after sorting them to separate bundles, see http://www.openembedded.org/wiki/Patchwork#Multiple_layers_sharing_the_same_oe_project_on_patchwork
For the record this is something I hope we will no longer need to do once the appropriate structures and automation are in place within patchwork. We're some way off that now though.