Hi!
I have some of those "buggy" displays (0.96") and — before finding these hints in the forum — I defined the colors matching the display.
// Color definitions (correct)
// #define BLACK 0x0000
// #define BLUE 0x001F
// #define RED 0xF800
// #define GREEN 0x07E0
// #define CYAN 0x07FF
// #define MAGENTA 0xF81F
// #define YELLOW 0xFFE0
// #define WHITE 0xFFFF
// #define DGRAY 0x2945
// #define LGRAY 0x528A
// #define ORANGE 0xFC02
// Color definitions for displays with buggy color system
#define BLACK 0xFFFF
#define BLUE 0x07FF
#define RED 0xFFE0
#define GREEN 0xF81F
#define CYAN 0x001F
#define MAGENTA 0x07E0
#define YELLOW 0xF800
#define WHITE 0x0000
#define DGRAY 0x528A
#define LGRAY 0x2945
#define ORANGE 0xFC02
I know, it's not the expert's way, but it works. 8)