I have the new iPad Pro 10.5”. Updated to 11.2.1 several days ago, most likely right away when that update came out. Just last night, my dock started relocating. It moved from the center to the left, and stayed there. I restarted, it was centered, and at some point when I closed the game I was playing, or Facebook, or something, it had relocated to the right. If I rotate the iPad, it never recenters itself, only restarting will do it.