Menu Bar Non Retina on rMBP 13"

[Dundonik]

I just recently purchased a 13" Retina Macbook Pro and I've noticed that the right side of the menu bar becomes pixelated/non retina randomly. I tried to google it and found no solutions
heres a screenshot of what I'm talking about

 

[MUBiomed]

Menu Bar Non Retina on rMBP 13"

My menu bar becomes non retina randomly when playing league if legends. Not sure what causes this. A restart reverts the menu bar back to all retina.

Not sure if applicable to you but could be related to a program you are running?