Loading screen flickers [CLIENT]

Every time, entering a new game, the loading screen has flickering lines and jumps. So far the only resolution is to Command Tab out and then re-open the client. This problem reoccured for every game started.

Issue began after installing Mac OS Sierra Version 10.12. Running on a MacBook Pro 16 GB (Graphics AMD Radeon R9 M370X 2048 MB Intel Iris Pro 1536 MB) -- (I do not use an external monitor)

This problem occurs both on the current League Client as well as the Alpha Client. Current client requires several Command Tabs, sometimes closing the client and restarting PC before it resolves itself. So far on the Alpha client I only have to Command Tab out once. Closing league/restarting PC not required.