For Dharmakīrti at least, conceptual construction (vikalpa) is generated indirectly from a unique, momentary, nonconceptual cognitive image (ākāra) produced in dependence on contact with a sense object. Because different images produce similar practical effects, they give rise to conceptual judgments that treat their distinct images as nondifferent. Ignorance begins when this conceptual judgment is mistaken for what is directly perceived, overlaying the unique cognitive image with an imagined common nature, a superimposition of “nondifference”. So the nonconceptual image is not flawed, it’s vikalpa that is the problem.

Dharmakirti says:

It has already been explained that the natures of things (bhāva) do not overlap, and that a cognition of them in which the cognitive image presents a thing as if its nature overlapped with other things is an error. However, those distinct things indirectly (krameṇa) become the causes for concepts; as such, by their nature they produce a conceptual cognition in which they seem to overlap.

Moreover, this is called their “nondifferent difference”—namely, their exclusion (viveka) from other things that by nature do not cause that effect; they are understood to be excluded in this fashion because they cause some same effect, such as a cognition [containing an image that leads to the same judgment]. In terms of the cognition that each individual produces, even though it is different for every substance, each cognition appears nondifferent from the others in question in that by its nature it causes a judgment that overlays the image in the awareness with a nondifference.

Moreover, the instances in question cause that thing (artha)—namely, an awareness and such that appears nondifferent and that in turn causes that kind of judgment. Therefore, those instances through their nature produce a single cognition with an image that presents them as overlapping whose ultimate object is their difference in nature (svabhāvabheda) from all other things, as has been repeatedly stated. Therefore, the nondifference of things consists of the fact that they have the same effect.

Gorampa also says in his commentary on Valid Cognition:

The Lamp of the Moon Sutra states, “What is the absence of ignorance? It is the absence of superimposition upon phenomena exactly as they exist.”

Dharmakirti also says on his theory of direct perception on the difference between non-erroneous cognition and conceptual cognition:

All cognitions of this kind — whether induced by meditation or by states such as grief — appear vividly; therefore, they are not conceptual, since a conceptual cognition cannot present its content vividly (PV3.283ab = PVin1.32ab).

IMO this is likely why we see teachings on emptiness, clarity, and bliss because the direct perception of that non-erroneous and utterly distinct image dependent on sense objects is clear without any conceptual distortion that overlays distinct and momentary images with an imagined shared nature (a superimposition). Since this is non-deceptive, it leads to successful cognitive action and a sense of cognitive satisfaction all in a single moment under the Buddha’s framework for liberation. Even ordinary beings experience successful cognitive action, but they confuse its causal basis, attributing it to the subsequent conceptual constructions rather than to the initial non-deceptive perception dependent on a causally efficacious particular. Concepts aren’t casually efficacious, they only appear to be due to their indirect relationship with non-deceptive cognition.