How come sometimes I see the same meme on the first and second page?

Meme ordering updated when you were viewing the first page.

But even when I click back and forth between pages it's still there.

Oh, well nobody can explain that. (Right devs?)

Did you click back in your browser or reload imgflip? Because your browser saves the data from the last few things you saw, so you might not actually go back a page but back in time, so to speak... You know what I mean? 🙈

Yea, lol I think I get it

try a browser refresh - then it should be fixed.

Happens to me as well, and sometimes even on three or more different pages.