Did it come that way or did it happen after you worked on it, was it gradual, all of a sudden or was always that way?
If it came that way the 3 posts may have not been pressed into their perspective holes and I would contact the seller about it.
If the seller /warranty is bad You might want to see how they react if you try tapping them in with a flat faced hammer and a piece of softer metal so you dont peen the tops of the studs to the point you cant get the clutch plate off but if you do just file off the edges so they are symmetrical again.
Its hard to see by your pic but it looks like only one is rubbing. Mask off the area and take a grinding wheel to the one stud and knock it down until it doesn't rub any more. By the looks of it it won't be by much because you've already worn a nice groove in the top case so you shouldn't have to take off very much.
Did it come that way or did it happen after you worked on it, was it gradual, all of a sudden or was always that way?
If it came that way the 3 posts may have not been pressed into their perspective holes and I would contact the seller about it.
If the seller /warranty is bad You might want to see how they react if you try tapping them in with a flat faced hammer and a piece of softer metal so you dont peen the tops of the studs to the point you cant get the clutch plate off but if you do just file off the edges so they are symmetrical again.
Its a manufacturer defect. Ask for a new motor or a refund.
I know what a bummer that is but if that stud is any indication to the attention that they paid in assembling that motor ... Then its not up to snuff.
Did you open the top of the cylinder head to look down inside where the Pistons at to make sure that there's no debris in there did you take the jug off to check the flow ports to make sure they are clear of obstruction and casting flaws?
If this is your first build there's some things that you need to do before you put that motor together to run.
Such as inspecting the flow ports, checking the Piston area or combustion area for debris that may have fallen down in there while cleaning up the spark plug hole.
These are all things that you want to do before you cook those gaskets onto that motor.