This is a known artifact of the fact that the SDL-renderer uses 16 bpp colours, while the engine uses 32 bpp. Compare with the OpenGL-renderer, which uses 32 bpp (but is not enabled in stable releases).
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This is a known artifact of the fact that the SDL-renderer uses 16 bpp colours, while the engine uses 32 bpp. Compare with the OpenGL-renderer, which uses 32 bpp (but is not enabled in stable releases).