In some fanfics, Naruto may ignore Sakura because he has his own emotional traumas to deal with. He might find Sakura's presence a reminder of things he wants to forget or move past, so he chooses to keep his distance. For example, if he has faced a lot of rejection from her in the past, he could decide to just cut her out of his life.
Sakura might initially be confused. She would probably wonder why Naruto is acting this way all of a sudden. For example, she might try to get his attention by calling his name a few times, but when he doesn't respond, she could be left feeling a bit bewildered.
There is a fanfic titled 'Naruto's Solo Journey' where Naruto decides to distance himself from Sakura. He believes that she is too focused on Sasuke and he wants to carve his own path without getting involved in their drama. This makes for an interesting read as it shows Naruto's growth in a different light.
She could be confused at first. She might not understand why Naruto is suddenly ignoring her, since they were friends before. So she might try to approach him to ask what's wrong.
He might be initially confused. Sasuke is not used to Sakura ignoring him as she has always been somewhat persistent in her attention towards him. So, he may be at a loss as to why she is suddenly acting this way.
Another reason could be that Naruto is trying to protect Sakura in his own way. He might think that by ignoring her, he can keep her out of harm's way. If he senses that there are dangerous enemies lurking around, he could be trying to create a distance between them so that Sakura doesn't get caught up in any potential battles or threats.
I'm not sure specifically if there are super - popular ones with that exact title. But there are likely many Naruto - based fanfics where Sakura has some sort of strained relationship with Team 7. You'd have to search through fanfic platforms like Archive of Our Own or FanFiction.net to find out.
It could mean that in a fan - created story (fanfic), Sakura is depicted as ignoring Team 7. Maybe she has some sort of conflict or just a personal choice within the context of that particular fan - written narrative.
One possible reason could be that something happened during the Kage Summit that made Naruto lose trust in Sakura. Maybe she made a decision or took an action that he didn't agree with. For example, if she sided with someone against Naruto's ideas regarding the situation at the Summit.
One possible reason could be that Sakura has finally grown tired of Sasuke's aloof and cold behavior towards her. She might have realized that she has been constantly chasing after him while getting little in return, so she decides to ignore him as a form of self - preservation.