I am not sure you would be surprised, but looking at the current projections, over a number of different colors on the
building, it is not a problem.
Projection mapping accounts for all the hues, their intensity, their albedo, their texture, their shape, and their orientation.
If there is a checkerboard yellow and green, then everywhere the projection lands on the yellow, that portion of the projection is color corrected (they remove yellow). Similarly, wherever the projection lands on the green, then that portion of the projection is color corrected.
Such corrections can only go so far. You're not going to get an image that is supposed to be white to look white bouncing it off a blue surface. But if the surrounding image is blue-corrected, they mind can be tricked it's seeing white.