One day when I pulled my ATS out of the safe I noticed oil droplets on the inside of the lens of the eyepiece. Doesn't seem like it harmed anything other than it bugged me.
It's the grease they use on the o-rings and threads of the fast focus eyepiece. It will seep out over time as it breaks down or gets thin. Especially if your safe is in a garage, or other place where it gets warm. It's not a problem, and doesn't affect the seal.