I just played a game in which I won but lost lp. Now during the game I had internet issues and had to DC (spectrum in my area went down, had to connect to my mobile hotspot) but I came back and finished with the team. Im not sure why I lost LP.
maybe because you dis-connected but i dont think this is the reason unless riotmade new rules
it´s not a bug but the sistem counted you as a leaver. it doesn´t matter if you come back and win. for the sistem you will be count as a leaver afk and you will lose lp. i know is frustating but riot doesn´t care about that. [slayer-jinx-unamused]
yep. as onionsan01 said no matter if u win if u was afk for some amount of time u will lose LP 
