It'll weep out of the shaft that the shifter linkage is attached to, and run down onto the mainshaft behind the belt pulley, down onto the bottom of the drivetrain, and ultimately onto the swingarm, back tire, and ground. They typically just weep a little and don't lose too much oil.
To clarify, the shaft will have some play in-out relative to the transmission (i.e. in line with the shaft itself) but shouldn't have much lateral movement (i.e in line with the shift linkage).
I'd suggest doing the following:
Raise the bike onto a lift and cover the lift in plastic. Spray the snot out of it from above and below with a full can of rubber safe engine cleaner from the local auto parts store. Get in there in all the little crevices the best you can with things like old toothbrushes and bottle brushes. Spray it again with engine cleaner afterwards. Then rinse it down. After a few good rides you'll be able to see clearly if that shifter shaft seal is leaking or not. If it turns out that the new seal is leaking, I'd talk to the shop who installed it before shelling out for another repair, as that seal should last far longer than 1-year.