Picked up starter chest. Then went to run and while running I noticed my items on my inventory "hand" were flickering. The chest most prominently. It was in the second slot of the bar.
*What I expected to happen was....the items to stay a consistent single color, shape, and value.
*What actually happened was items flashed erratically at me.
Steps to Reproduce:
1. start new game survival, normal, large biomes
2. choose a starter chest as well.
3. grab items from chest before breaking chest, and allow the chest to fall into your "hand" bar WITHOUT moving the chest yourself.

these are all the things I had done. I apologize, but an image wouldnt do this justice unless it was GIF, which, Im wayyyyyyy too lazy to do all of that.
sorry guys. thats how it happens to me

heres some system specs for you though

dual core phenom processor
7200 hdd 500 gb
4 gigs ram (minecraft only allocated 2, and the first is loaded with the game)
Win 7 home Ed

other than that i cant be any more of a help. Im a novice in computers, not a master. There may be some things ive forgotten. If you need any other specs, let me know.