Strange squares while playing GTA V

[-Foster- 6]

Recently, having entered GTA V, I saw a strange green square in the left corner of the screen, next to which, while turning the camera around the character, several more of these may appear for a while. If at this moment to minimize the game and re-open, then when you turn the camera, the game freezes. What can it be and how to fix it? Any help would be greatly appreciated.