Weird thing happens on right side of screen

[Jumballi]

When on minile, and I slide right on the right side of the screen, a pic of a 5-toubun girl shows up, not sure why?
https://imgur.com/a/NYHoGMc

 

[Jendrej]

Read the announcement バカ
https://mangadex.org/thread/67299

 

[421cookies]

Weird indeed. They said it's best girl but I can't find Yotsuba anywhere.

 

[DANDAN_THE_DANDAN]

That's odd. I'm seeing best girl clear as day.