I'd give that lock a good flush out with WD and then put tape over it when parked to stop water pooling on it (even though the flap covers it).
I know there are mixed opinions on what to lube ignition barrels with, some say dry lube like teflon, others use nothing more than powdered pencil lead. I use silicone grease as I already have some for other jobs.
There is a bloke on another forum who has just had to spike his with a screwdriver (different bike but still Suzuki), his was stored in a garage. Maybe it's the cold weather or maybe it's bad design.
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Bad design was blamed in this instance, it's a known issue for that bike (but not for Vstrom btw).