Client bug where the style reset to preseason 2014

[CLIENT] Style/Format reset to early 2014 Preseason style

I opened the client like normal, nothing different and I noticed all of the style was a bit off. There were boxes around each ranked category, no champion mastery anywhere to be found, and the match history was the old style where there was no in-depth info. There was no mastery under the "Champions" tab either. Very strange. I restarted the client and it fixed itself but I don't know why any of that would happen. Just wondering if anyone else noticed? Thanks!