Yep, Infiniti made the bizarre decision to replace the G37 with the Q60, but then keep making the G37 and call it the Q40. I imagine it was an attempt at being able to claim a lower entry-model msrp. Might also have been a move to keep the factory lines running until the capacity could be shifted to a future crossover. Either way, it was pretty weird. But then BMW did the same thing with the 3 series and 4 GranCoupe, for whatever reason. I will never understand luxury brands. They'll make two of the same car but then claim there's no demand for another model that would fill a completely vacant niche.
At best, it made the new all-Qs naming even more confusing. At worst, it lost a lot of money for dealers who had a superfluous model sitting on the lots at an uncompetitive price.