I recently dodged a ranked game at 0 lp and ended up having -3lp. This was not just a visual bug as you can see in the picture. I don't really care about those 3 lp, i just wanted to know if this is intended or not.
Intended. It's penalty for queue dodging.
The penalty for a dodge in ranked is a loss of 3 LP, which still applies even if you're at 0 LP already. Dodging is the only way to wind up at negative LP.
It is completely intended,that also often happens when you (i think) enter a fresh division,and so to not get demoted,you instead get negative LP
