Aimlessly wandering around to avoid AFK detection

I believe you have to get in exp range every so often or it automatically marks you AFK.

I'm so terrified of getting reported whats next? am I going to hell too? come@me

{quoted}

You have to actively participating in the game, or I automatically mark you as afk.

Sorry for the up but i am really interested in understanding how it works.

I've just played a game where I decided to open my lane (dont judge me, game was really lost - ,-) just wanted to make it as quick as possible and go next).

However, I didn't wait in fountain, i stayed behind my T1, kept farming (more or less ==> I was not really trying to last-hit but I was cleaning waves when they were reaching my tower and that no one was around.). I was (more or less, again) spamming skills, moving, talking in chat and so on. I did not alt-f4 or something (or at least for more than 1 minute in a row).

At the end I had an average level of experience (maybe slightly behind, but not that much). But I still get that leaverbuster. My final KDA was 1/1/0 . Any idea ? The game : https://gyazo.com/311c85f29a88b52346a75da424afc21a

PS : i'm not complaining about getting this leaverbuster. I was not really playing seriously, system detected it and punished me. All fine, but now I am curious to understand how it works.