Every computer will generate different colors due to driver/os/hardware differences when rendering anything. these differences are often imperceptible to the eye by easily grabbed via browser apis. by randomizing the results just a tad it defeats the trackers.
fingerprinting mechanisms use pixel coloring to help fingerprint you. browsers have implementations that fuzz pixel colors to prevent this fingerprinting often in imperceptible manner. Think shifting pixel alpha values by a random +/- 0.3 values; range was arbitrarily chosen for demonstration purposes.
np, i wouldnt worry about it for this website just leave your settings alone until you personally notice an issue. and even then…