Well, vger (as of right now) no longer directly attempts to deliver to gmail/google/googlemail just to get the ridiculous backlog out of the primary mail paths. Vger (1 machine) is kicking all of that queue over to 8 other machines and letting them go try to get that delivered and queue up somewhere where it's not going to cause everyone else pain.
This should, at least for now, settle out several things, but if you are seeing mail wonkiness give postmaster@ a ping and I'll take a look.
Also if you are on Gmail and doing kernel dev, might be worth looking at other email providers.