That doesn’t look like enough to be gear lube. Grease and gear lube smell different. Pressure test the drive see if inout shaft is leaking but that looks like a fairly typical separation of the oil from the grease . Would not worr6 about what I see there.
My first thought was gear lube and smelled it, does not smell like merc gear lube at all. We did lose a bit of level in the bottle this year BUT I drained and refilled the drive while it was off last fall so once the air worked it’s way out the level dropped. Or at least that’s what I told myself!
After changing in the fall, First run of the year I typically get some level drop as the air works out. Then after that it I stable rest of year. Onky time it dropped was when I had fishing line in the prop seal …
