game randomly ended

I was playing a normal draft on summoners rift and the game suddenly ended without warning and my team was given a loss. There was no ff message in the chatbox and our nexus was not close to dying but the game suddenly ended, the defeat animations went off and the defeat menu popped up.

I have not been able to reproduce this issue, I have no idea what could've caused it so idk where to start to attempt a reproduction. I've been playing lol for a few years now and this is the first time i ever remember this happening.