Interesting tutorial - it’s a pity that VfR doesn’t support the simple GI saturation anymore.
SIdenote: an other pitfall is visible at the tutorial too - the red color is set to (255,0,0). I suppose so the white walls are at (255,255,255). For Vray it means 100% of the incoming light is diffuse reflected. At the real world the brightest white isn’t so high diffuse reflective, more than 80% isn’t possible. Since we can’t not set the global limit at 80% like at VfR2, we need to set all colors at 80%. If not, than the relation between direct and indirect light is wrong. At the tutorial we can see a complete red room by a red floor only. In reality it wouldn’t be so strong.
So, the strong color bleeding maybe be caused by 100% white walls and to bright color texture. The indirect light transport isn’t right stopping.
(The GI limit and the saturation options are available per manual editing the saved option file only.)