It is not a well known fact, but JYP had planned Very*3 as the next song for Twice after Cheer Up.
But, because Ennik Douma was still in JYP at that time, and there were talks about the people running IOI and JYPE at that time, he decided to give the song to IOI.
While Very*3 became the most remembered song of IOI, 6 years later after most of the IOI members ' careers crashed and burnt, it can now be safely said that this song was wasted and Ennik did avenge Twice in a way she never really expected.
TT is Twice's greatest hit, and using it after Cheer Up was an overkill from which Twice began to take a very different course.
Ennik being in the IOI also unwittingly helped Lee Jieun significantly.
If things went to plan, TT would have been released on early 2017, burying Through the night completely.
As chance would have it, Knock Knock, a weaker song than TT, got to fight TtN, and since then Twice has not been able to defeat Lee JIeun.
TT beating TtN would probably have sent Lee JIeun home, after Laboum and Suran delivering the finishing blows, and she would be playing supporting roles (the debacle of Moon Lovers showed that she was not a leading actress material) and hardly ever remembered, instead of rising to the world's #9 singer, the mortal enemy of BTS and a world figure who was invited to Cannes and Milan.
tl,dr. Ennik Douma, who was not selected to Twice because she was too young back then, had her revenge by significantly changing Twice's courses by making JYPE give Very*3 to IOI, and the greatest beneficiary of this, as usual, was the sworn enemy of KPop.