Ranked game issue

Hey, i really enjoy playing Leaug of legends and ranked games, but its someting that i think is pretty stupid. I playd whit my friend and he was in the game to he got lvl 5 then he lost internett and dident come back. And ofc we lost the game cus of feeding from top and mid, so my friend was afk from the 5-8 min and we dident get lose prevented and i lost 24 LP from a 4 v 5 game... Is this a bugg or someting u rly should fix (Cus i lose more Lp by plaing 4v5 than winning lp in 5 v 5)