There's so many wrong details here compared to what actually happened
Finana wanted to go to a Honkai event in New York but she has strict asian parents so she asked Pomu to meet up with her as a sort of guardian.
They had a girls only stream but Finana decided to invite Uki who lived close for some reason.
Pomu wasn't aware Finana invited him until the last minute and she took most of the backlash from unicorns since the collab was on her channel.
On Finana's first stream back from the trip, she admitted she hid Uki's presence from her parents.
On Pomu's second stream back (first was a JP Phasmo collab) she said she didn't know Uki was going to be there until the day of the off-collab stream.
Given how bratty Finana is (only wanted to do her own things, didn't want to go where Pomu wanted to go, made Pomu foot the bill because Finana maxed her cards on the first day), she probably bratted herself into inviting Uki to the stream, so that they "could have a special guest like all the others!"
This is all backed up by their streams. Don't post if you're not familiar with the topic or don't remember details well