So, last night I was playing the game normally and I zoomed out and the objects and stuff started flashing random colours. I exited the game and re-opened it and it started doing it again but this time it was the entire screen flashing (in game mode, the loading screens were fine) and going odd. I swear if I was epileptic it would have given me a seizure. I wish I would have print-screened it to show you guys but it was freaking me out and I didn't think of doing it.

Youtube videos were also going odd. I would get white lines going through them. I actually thought my Mac was dying on me.

Today it is fine again

What the actual hell was that?

My specs:

Out of curiosity was it connected to an external display? I have had this occur with my macbook pro (2010) either connected to one and sometimes not. Usually a reboot helps. However it does happen randomly though mainly after being put to sleep a lot. I haven't had any issues with my iMac 27in (Late 2012), the display sleeps all the time, but its always online since it is my media server. Not sure if the Sims 4 would be having any issues or not as I don't own it yet. Am a little upset with Maxis and EA for stripping more things out of the base game and there is still so much content for the Sims 3 that i still use.

Nope, I was playing it on my iMac's display :/ It's really odd. It haven't happened since.