>>28651015In one page, it says Rockruff has a secret, and, by the way, the starters also have a surprising secret. On another page, it does say something like "What will their evolutions look like?" with Rockruff and the starters grouped together. Though, personally, I think it's just because they were all shown off in Corocoro for the first time with that issue. If you trust the Riddler, Komala doesn't evolve either, which would explain why those four but not Komala are in that group for that phrase.
Plus if they had the same secret I think they'd show off all the evolutions at once, especially since the starter's secret wouldn't be very surprising if they showed it off after Rockruff's and it was the same thing.
We'll see which way it'll be either way.