Random loading screen freeze

I was playing a ranked game and it apparently froze but my ping was still moving. Everyone was at 100% with a Sona at 19%. As I said, my ping was still moving around and such so I just assumed that Sona was making the connection horrible. I got irritated so I exited league and relaunched it so I could speak to a friend. I reconnected after speaking and the game started. Turned out it had started without me. The loading screen lied. I was afk for 20 minutes in a ranked game and I didn't even know. Now everybody is reporting me for being "afk" but it was some technical issue. Please tell me this was a 1 time thing and it wont happen again.