The Ninty president did say on the 9th Feb that "action would be taken", which is where I get 2 from.
Dunno the whys and wherefores but it might have been the case that this was (a) not a slam dunk infringement; and (b) wasn't considered a material issue to spend the time, Yen, and effort on dealing with. No point going for a 70% chance of success case, and suing for damages when nobody has heard of the game, and there's no money to claim even if you win. Now that they have a lot of cash coming in and are occupying a lot of headlines, many of which associate Pokemon with guns, Ninty may feel it has gone too far and is worth their time to tackle.