Just an Investiture/Stormlight theory:
So in WoK, Kaladin uses an absurd amount of Investiture while only at the First Ideal to pull all the arrows to him and it proceeded to drain him dry of Investiture. Teft said "Your skin is ashen, lad." While Lopen described him as "white." The effects seem similar as someone who used duralumin with pewter for the absurd pewter drag. But his draining of color, since Kaladin is of a tan complexion, seems to tie into Awakening with when Breaths/Investiture is imbued and then released, it causes loss of color of the object. In this case, Kaladin was the vessel, hence why his color was drained.
















