i'll just copy and paste from where i read it
According to this blog (which has been reliable in the past), the following note was in the latest issue of Monthly Ikki:
Which is basically Q saying that at first she thought of making volume 19 thicker than normal and ending the series there. But in the midst of drawing she ended up wanting to draw more, and that it would be better to extend the series to volume 20. She proposed this idea to the editors, and they are very excited about it, but are still waiting to hear back from the higher ups. Q will inform us once a final decision is reached.
ngl i saw that coming what with how much stuff still had to go down before the conclusion but i'm still stoked as all hell for an entire additional volume god bless hayashida
plus ending on volume 20 sounds a lot nicer than on volume 19 lmao