Another Easter Egg Question

Do I have to jump between pages for the egg to spawn or is it possible for the egg to just suddenly pop?

Not sure if it's the case, but I feel like I have 1-2 occasion where the egg suddenly appear on the page when it wasn't even there before.
Doctorn doesn't notify me but the egg is there anyway.

Edit: I'm also curious if opening multiple tabs at once in PC gives a better chance of finding the eggs.
Like for example, blasting open all locations in the city menu (almost) at the same time.

you have to enter a new page and theres a chance of an egg spawn

Alright, it's probably just my eyes playing trick on me or I'm just simply not noticing Doctorn's notification.

I've experienced the same and read others stating that eggs have a chance to spawn at pageload, but also have random timers to spawn while viewing a page. But the only consistent thing I've found is that nobody really knows the exact mechanics besides the devs.  There's apparently "invisible" eggs to catch script users, and I'm sure other hidden mechanics that dictate when and where they spawn. 

I'm well aware of the existence of that invisible egg, but I'm not sure about the other mechanic.

Whether there's a chance for an egg to appear after idling in the same page or not is something that I'd like to confirm.