A flurry of rumors about Han So-hee surfaced on October 16, linking her to an Instagram account owned by an unknown individual, Z, who left mean comments on Hyeri's official account.
Under one of Hyeri's Instagram posts, Z left a series of comments: "Your unnie's (Hyeri) and Ryu's (actor Ryu Jun Yeol) follower count combined can't beat (Han So-hee's)", "How stupid are you to believe one can 'fill up' 17 million followers?", "Must have been nice to see Hyeri finally getting some likes in a while because of Han So-hee. How sad that it's all gone now."

Furthermore, the account was created in March; it coincides with the revelation of Han So-hee and Ryu Jun Yeol's relationship and the subsequent controversy surrounding the two and Ryu Jun Yeol's ex-girlfriend, Hyeri.

The fact that Jun Jong Seo was following Z has deepened suspicions that the account might belong to Han So-hee, especially considering that Jun Jong Seo follows only 19 accounts and has no reason to follow an internet troll with no connections to her.

"The social media account revealed by the media does not belong to Han So-hee.", the agency stated.
ANDMARQ, the agency representing Jun Jong Seo, has stated they cannot confirm the matter, citing it as "the artist's private life".
Meanwhile, in March, Han So-hee and Ryu Jun Yeol were seen having a trip together in Hawaii, the United States, sparking romance rumors; the two soon admitted their relationship.
In the process, Hyeri wrote, "Well, this is fun", on her Instagram story, seemingly in response to the rumors about Han So-hee and Ryu Jun Yeol.
▶ [SBS Star] Hyeri Unfollows Ryu Jun Yeol After Him·Han So-hee's Dating News; Also Posts, "Well, This Is fun"

Hyeri's post ignited speculation that Ryu Jun Yeol moved on to a new romance with Han So-hee 'too soon' after his breaking up with Hyeri.
Then, Han So-hee made a post on her social media denying the speculations, further intensifying the controversy.
As the situation escalated, Hyeri and Han So-hee apologized on their social media accounts.
Ryu Jun Yeol and Han So-hee announced their breakup 14 days after confirming their relationship.

(SBS Star)