Bug with the Ranked

Ok this only happened to me once so far, and it was kinda random but someone had left a ranked que and then everything went normal when getting put back in que, then pressing accept to go to champion select, then this is where the bg happened, the screen flashed then it said loading server data and it stayed there for 5 min, didnt hear nothing going on with the sound like everybody else could see. So i closed to game and relogged, then i got the 5min bann for leaving a ranked que, i hardly ever get banned and didnt like the fact i got banned (even if for 5min) from a black screen bug, Kinda like a soft freeze.

PS sorry didnt take a screenshot. If it happened a again i will be sure to take a screenshot