Uttamur T. Vīrarāghavācārya discusses the reasons for having to deal with epistemology while trying to understand dharma in the context of PMS 1.1.3: We need to deal with epistemology because there are too many disagreements about what dharma is and how to know it. Here he summarises the Lokāyata position:

The position of the Lokāyatas is [as follows]. In ordinary experience (loka), there should not be distinction between what follows the rules (nyāyya) and what does not, or not (there should be a distinction)*.
The [condition for knowing] about dharma, adharma, etc. does not exist at all.
Since it (dharma) is understood in each time different ways by the upholders of the various opinions (mata), only its absence is apprehended.
Therefore, the condition of what should be investigated?

like nyāyyānyāyyavibhāgo mā bhūt, mā vā. dharmādharmādikaṃ nāsty eva. tattanmatasthair anyathānyathā tadabhyupagamāc ca tadabhāva eva pratīyate. ataḥ kasya niṃmittaṃ parīkṣyam iti lokāyatamatasthitiḥ.

*I am puzzled by the mā vā. If this reading of the subcommentary by Uttamur T. Vīrarāghavācārya is correct, the Lokāyata position is described as altogether sceptical. They do not even maintain that there can be no distinction between nyāyya and anyāyya. How would you interpret the mā vā?

Vīrarāghavācārya was a 20th c. Viśiṣṭādvaita Vedāntin whose editorial and commentarial contribution to his school will remain impressive for many generations to come. Personally, I am particularly pleased by his attempts to think along the tradition in a creative way.

Within his subcommentary on Vedānta Deśika’s Seśvaramīmāṃsā, Vīrarāghavācārya is at times closer to Viśiṣṭādvaita Vedānta than Vedānta Deśika’s pro-Mīmāṃsā attitudes. At other times, he just elaborates further on Vedānta Deśika’s hints. In one of such cases, he describes how the choice of words in Pūrva Mīmāṃsā Sūtra 1.1.2 (codanālakṣaṇo ‘rtho dharmaḥ ‘Dharma is that goal which is known through Vedic injunctions’) was not at all casual. Rather, each word had a direct meaning and also further suggested something more. For instance, codanālakṣaṇa is not just the same as codanāpramāṇa, but rather suggests that the Vedic injunction also defines what dharma is. dharma is also to be interpreted etymologically as ‘instrument of dhṛti‘, where dhṛti means prīti ‘happiness’. Similarly, artha indicates that bhakti is the result to be achieved, consisting in pleasing God. Then he sums up:

Through the word dharma, which means instrument for dhṛti, Jaimini also suggests that this ritual action devoid of desire which is a purpose in itself (svayamprayojana) is different than the instruments for the results consisting in the four human aims, which are expressed with reference to their own contents (svaviṣaya) [only]. [He suggests it] because through this [word dharma] also pleasing the Revered one (bhagavat) is communicated (uddeśya).

dharmapadena dhṛtisādhanavācinā caturvargaphalopāyāḥ ye svaviṣayāḥ vācyāḥ tais saha anlat svayaṃprayojanaṃ niṣkāmakarmāpy asūcayat bhagavatprītes tatroddeśyatvāt.

In other words, bhakti points beyond oneself, to God, whereas all other purposes remain confined to oneself.

To my knowledge, Veṅkaṭanātha’s Seśvaramīmāṃsā (henceforth SM) has been commented upon only once in Sanskrit, namely in the 20th c. by Abhinava Deśika Vīrarāghavācārya.
Vīrarāghavācārya continues Veṅkaṭanātha’s agenda in reinterpreting Mīmāṃsā tenets in a Viśiṣṭādvaita Vedānta way.

On the meaning of dharma and on the polemics between a sādhya and siddha interpretation of the Veda, he writes:

Deities need to be pleased (ārādhya), what needs to be realised is the result.

(ārādhyā devatāḥ, sādhyaṃ phalam, ad SM ad PMS 1.1.1, 1971 edition of the SM, p.10)

Similarly, within the commentary on SM ad PMS 1.1.2, Vīrarāghavācārya interprets a quote by Parāśara Bhaṭṭa according to Maṇḍana’s distinction among various deontic concepts and then adds a further level:

The instruction which has necessarily to be performed is the command. The permission is the instruction which presupposes a desire for the experience of a result which is not forbidden. It has as content something desirable. An instruction having as content a forbidden purpose (as in the case of the Śyena) is a permission which has occurred automatically [but will be later subdued] (āpātānujñā).

The added level is labelled āpātānujñā. This is, as far as I know, a neologism. It indicates the fact that prescriptions about malefic sacrifices are not the Veda’s final words on the topic. They look like prescriptions, but in fact:

1. like all other textual passages presupposing human desires, they are only instructions about how to reach something, they do not state that one should desire it.
2. on top of that will then be sublated insofar as they presuppose a purpose which is prohibited in another part of the Veda.

Point 1 is a standard Mīmāṃsā devise to justify Vedic passages about malefic sacrifices. Vīrarāghavācārya adds point 2 to the landscape, thus highlighting that the textual passages about malefic sacrifices are ultimately sublated insofar as the purpose they presuppose is prohibited.

Vīrarāghavācārya probably formed the term āpātānujñā on the basis of āpātadhī. This is a term introduced by Rāmānuja and discussed at length by Veṅkaṭanātha. It means `automatic understanding’ of the Veda, the one one gathers while learning the Veda by heart without caring for investigating into its meaning. Such an automatic understanding will be later revised while one investigates the meaning of the Veda. Vīrarāghavācārya implicitly suggests that it can even be completely reversed.

Have readers ever encountered the term āpātānujñā?

I already discussed here my admiration and fascination for Uttamur T. Viraraghavacarya and his work. Vīrarāghavācarya is known in his Tamil works as Uttamur (or Uthamur) T. Vīrarāghavācarya (with various graphic variants) and in his Sanskrit works mainly as Abhinava Deśika Vīrarāghavācarya.

He wrote countless books, mostly commentaries on Viśiṣṭādvaita Vedānta books in Tamil, Maṇipravāḷa and Sanskrit. However, he also wrote directly on texts he deemed important for religious, e.g., stotras and Upaniṣads, theological, e.g., Udayana’s Nyāyakusumañjali, and philosophical reasons, e.g., Kaṇāda’s Vaiśeṣika Sūtra and Pāṇini’s Aṣṭādhyāyī. His commentaries display his originality and deepness as a thinker, an instance of which has been discussed here.

The Viśiṣṭādvaita Vedānta community also reveres the figure of U.T. Vīrarāghavācārya, so that one can find on the web several interesting webpages dedicated to him and many of his works have been uploaded on archive.org (mostly under the name “Uttamur T. Viraraghavacharya”, see here). However, I could not find in any library or catalogue a copy of a text he refers to in his commentary on Vedānta Deśika’s Seśvaramīmāṃsā, namely his Upayukta Mīmāṃsā. According to the way he presents it (in his commentary on the beginning of the SM), this should constitute an attempt of making Pūrva Mīmāṃsā consistent with Vedānta, thus a very interesting topic. It is also referred to, for instance, in this and this page dedicated to U.T. Vīrarāghavācārya, still not a copy seems to be available for purchase (or download).

Do readers have suggestions about where to look for a copy of it?
(I already wrote to the Uttamur Swami Trust)