App sorted order on home screen ??

I previously had an iPhone 5 and recently bought a new iPhone 7.

I know that when you download apps, they appear on your home screen in the order of when you downloaded them, with the most recent app placed last in the list of apps. However, when I downloaded my first couple of apps, they appeared in a different sorted order. See below.



My first apps I downloaded were:
1. Youtube
2. Wikipanion (this should have been after Youtube, but it was placed before Youtube)
3. Fidelity (but this was placed before Wikipanion).
4. I then downloaded ESPN, and it was put after Fidelity. I then deleted ESPN and downloaded it again. Now it's listed last, and all subsequent apps are in the regular order (most recent app is placed last).

Has anyone experienced this ordering with their first apps?

 

I was wondering why the first few apps did not get placed in the order that was expected.

 

I downloaded them one after another, maybe 30 seconds in between. But I've done that before on my previous iPhones, and they got listed in the right order.