Couldn't Connect, Then Reconnected and Finish the Game, But got AFK Penalty

The game was in the loading screen (for a long time too), then at 99%, it said the internet was not working. But the internet was working fine for my computer, my phone, my ipad. everything. Then I had to close the game then reconnect. I joined my team even though the game already started and finished the game with them. The Leona on the other team said the loading probably had issues cuz their computer overheated and it took long to load (I don't remember exactly what they said but they took accountability). However, at the end of the game, I didn't get any loot because I got the disconnect penalty. I don't understand why I get penalized when league client had issues and also I was disconnected for a short time.