Black flashing boxes on landing screen

Dear riot,

I've have been suffering from this weird bug, ever since i updated to the new client.

Every time i log on, i see black boxes flashing on and off the landingscreen, and it's really annoying.

Also if i am in a queue, i have black flashing boxes, but also an overlapping of the previous screen (landing screen or store).

I have reported this bug a few times now, and after a few patches, it's still there.

Pls riot tell me how I/you would be able to fix this, and why this is happening.

pls, a reply would help a lot!