Extended black screen before loading and exiting game [Client?]

Every game since patch 7.9 be it ARAM, Regular, or the Thresh game (I dare not try ranked), I get an extended black screen on loading into into the game, loading and loading into the post game lobby. It does not crash like the other black screen bug I have seen. However the length of the black screen is severe sometimes even lasting a minute - which in the beginning of a game can be a big problem. If I alt tab out the black screen persists both on tab out and on clicking back into the game.

There is no special instructions on how to reproduce the issue - you simple enter a game and it occurs - I've tried playing on both low spec mode and regular mode thinking it was maybe a graphics loading problem (neither resolve the problem). My ping usually runs in the 40's to 50's if that makes any difference, but I had no problem until the 7.9 patch. I literally get this EVERY game no matter the game mode.