12 f2 made in china really tight to mount

I recently brought a 12 f2 from B&H and surprisingly found it is made in China:-( as stated on the outter box and at the back of the lens. It has a big issue of being really tight to mount onto my GX1, I have to really force it. Tried in local store, an saleman says it's reallt tight to mount on a store GX1 as well. Tried other Olympus lens mount on easily onto my GX1 (Such as 17 f2.8). Quality wise it's not  sharper than my 14-42 powerzoom. Anyone has experience with 12 f2 on Lumix body, especially GX1? Does yours mount on easily? Is it made in Japan or China? Should I return the lens? Any input is much appreciated.:-P thanks.