First, you do need to focus on something quite far away to qualify as "infinity".
Second. When you get good focus at infinity, what does the distance scale on the lens say? Is it at the infinity mark?
If the hard stop of the lens is at some point beyond the infinity mark and your focus at infinity (RF images coincide) shows the lens at the infinity mark, then I'd say its absolutely no big deal and your particular lens is able to rotate a bit further than we expect. Not sure why....lower tolerances in the factory? Maybe, but who knows...