negative LP bug RANKED (GAMEPLAY)

So i accidentally discovered a bug or exploit that when i was a zero lp in ranked and left the lobby or dodged a game normally youd get minus 5 lp. but for me it would go to -3 lp and lock there if i lost. the first time it happened i was able to lose about 5-6 matches in a row without being demoted to the previous rank. my lp was locked from going down at -3 lp in my current division. further more if i won, it would just add the lp like nothing was wrong. and also i was able to replicate it again when i got to 0 lp again just to see if it wasnt a one time thing. i dont think this is part of the game because normally at 0 lp if i lose 2 matches or so i get demoted. so its worth looking into because people can take advantage and lock their lp until they win so they never go down in rank. only up.