A new story was added to the Canalave Library, 2nd floor, 3rd green bookcase from the right. I'll put all the text here for easy reference:
This book is titled "The Sea's Legend." It's a text that was only recently discovered, and its ancient letters were decoded. Once upon a time in the East Sea, there was a Pokémon known as the prince. A brave human asked Pokémon living in the sea to let them see the prince.
Mantyke, Buizel, and a Qwilfish with huge spikes acknowledged the human's bravery and joined them. Together, they set off in a boat over the sunset-streaked sea, sailing through the ocean gate stretched over the waves.
News of this reached the ears of the prince, who went to meet the brave little party at the Seaside Hollow.
What is notable of this text is the emphasis on naming a location that doesn't exist currently; Seaside Hollow. As well as describing a unique appearance of a Qwilfish.
This can go with the current Riddler Leaks where one of the riddle images alludes to Qwilfish getting a regional variant/evolution.
A new riddle mimicking this story where the Pokemon are swapped to Cursola, Eelektrik, Clobbopus and Inkay. Which being all sea-dwelling Pokemon that aren't water types alludes to Qwilfish losing its water typing.