I expect a German stab soon (how soon is hard to say without knowing how long until the next build phase). I'm guessing it's currently Summer, and the stab is coming this very turn.
He has to be alarmed by the developments in Turkey - if Russia picks up 3-4 supply from currently Turkish cores, a successful German stab flies out the window becomes vastly harder to manage. Which means he has to be feeling intense pressure to strike before Turkey's imminent collapse pays off for Russia.
Similarly, while neither player is totally safe in the west, Germany is mostly safe. Worst-case, it would take a couple years for him to actually be driven out. Russia, on the other hand, has precisely one unit (F NOR) to defend three supply (NOR, SWE, STP), and has very little chance of getting Turkey to trust him at this point - sure, Turkey would probably agree to a cease-fire rather than face destruction, but he would have to keep most of his forces down there anyways because Turkey would likely attack him in a heartbeat rather than face a third Russian invasion.
More tactically, I look at that convoy to England and wonder who gains. Sure, Russia gets a supply next build phase. But in the mean time, it ties down a Russian army where it can do nothing at all to impact the home front, and simultaneously is guaranteed to piss off England and ensure England is not willing to agree to a cease-fire with Russia (assuming he takes Liverpool this turn with it). Which means while it's nice for Russia if Germany is on the level, it's great for Germany if Germany is planning a stab. And Germany supported that convoy...
