I don't think it's 100% consistent, but yes - I think they're off-center.
You can USE it in planning your coil placement.
Since the cap let's you pop the airhole wherever you want, you can kind of make the legs shorter if you want - by using that angle...
This one (which is a good reference for a nifty way to get the legs in the holes) looks pretty straight.
But this is angled...
If you look at google images of nuppins, I'd say "most" have the offset.
You can USE it in planning your coil placement.
Since the cap let's you pop the airhole wherever you want, you can kind of make the legs shorter if you want - by using that angle...
This one (which is a good reference for a nifty way to get the legs in the holes) looks pretty straight.
But this is angled...
If you look at google images of nuppins, I'd say "most" have the offset.