This is not a filler!
Release of the fourth volume of the novel "Boruto: The New Generation of Naruto" is scheduled for November. In the story were descriptions of the arch of the school trip, The author will again perform Kou Shigenobu.
So novel is the source of actual story now? What a clutter of writing this Boruto series has been.
Finding something from a novel that will happen in the anime doesn't make it less a filler. Its still a filler. The only canon source of Boruto right now is Boruto manga write by Ikemoto/Kodachi.
Taking ideas from non valid source will only cause a contradiction if they starting to flow differently at one point of time.
Novel-anime is just another story but not the actual one. The actual one is Manga-anime.
The first 18 episodes+Gaiden+Boruto manga-anime adaptation.
The room for novel is if something that happen in the Novel happen also in Boruto manga.