DJM-900NXS grounding terminals askew

I've bought a new DJM-900NXS this week. First of all, it's a great and solid mixer! Besides two CDJ-2000NXS's, I also own two Technics turntables. When connecting the ground signal to the grounding terminals on the DJM-900NXS, I've found out these terminal are a bit askew. It seems the screw-thread in the mixer is a bit askew. Also, the grounding terminals are very stiff. It was quite hard to unscrew them. Is this normal? Are there more people discovering the same? Before, I've owned a DJM-850 mixer. The grounding terminals on this mixer were a lot more supple and were not askew.

BTW, English is not my native language, so I've used Google translate for some words. I'm sorry for mistakes in my English.