The present article proceeds from that stream of Turcological research according to which the category of “exception”, within the context of (Turkic) vowel harmony, is to be regarded as at least misleading. From a historical point of view, the perfect vowel harmony of contemporary Turkish may be considered a later development which evolved from a primitive, regularly disharmonic system. Through a thorough scrutiny of an 18th-century Armeno-Turkish text, we add new arguments to the debate, by observing that the vowel phonology of Turkic languages seems to have been ruled by at least two colliding processes: a primitive, regular disharmony-triggered morphemic marking [RDMM] versus a transmorphemic rightward vowel harmonising [RVH]. A possible interpretation of some local “disharmonic” phenomena — fossilised remains of a primitive stress assignment? — is proposed here.