At what time the notification of new mangas releases pops up?

It depends on your timezone
In my time new manga releases at 5:30pm (PHT)

I get mine after 3am and I am from California in the us

I got mine at 6:00pm last week it change and it became 7:00pm to 7:30pmMaybe it depends on what time the manga is release and the website just pick what time is better to release an update so you can read more at the same time and you will get less update. You don't have to worry missing a manga to read because they release it at the same time.....hope it helps (=・ω・=)