I just made a Scotch ale about 4 days ago with OG=1.088. Fermentation temperature is about 60 F. I pitched a 20-oz starter in 3 gallons, and fermentation started up within 12 hours, then it had a huge krausen for about 2 days, and now it's already fallen back in. Time to check the gravity -- this might be a really fast yeast, I'm not sure. Sure seems like it. Is it possible that it's already finished fermentation for you when you weren't looking? Check the gravity, that's the only way to know for sure.