Tenjin agreed to send Yato and Yukine up to Takamagahara to confront Bishamon for taking Hiyori hostage on the condition that afterwards Yato would sever ties with Hiyori.
In Episode 6, when he returns, Tenjin brings it up and he wields Sekki to cut ties with her but she keeps refusing. However, it never shows him actually severing ties with her. Regardless of that, I don't think Tenjin would allow him to break his agreement. Later on in the episode, Tenjin and Tomone see Yato chasing after Hiyori and Tomone says, "It seems they haven't severed their ties at all."
Now, I'm sure that they said when a God severs ties with someone from the Near Shore they lose all memories of that person. It seems like Yato is frantically trying to get her to know him again, and she seems a little more distant than before. So, it definitely seems possible that he did sever his ties to her but then relentlessly harassed her to get her to know him again as sort of a loophole to his agreement with Tenjin. However, if that was the case, I don't understand why she would have remembered Yato was the one who helped her classmate when her classmate approached her later.
So were her ties severed or not? If they were, how could she remember these details from the past about Yato?