After the verbs dyut 'to shine' etc., the terminations of the parasmaipada are optionally employed, when the affixes of luṇ (Aorist) follow.,
The Dyutadi verbs are 22 in number, to be found in Dhatupatha in the Bhuadi class. By the use of the word द्युद्भ्यः in the plural in the sutra, the force is that of &c. These verbs are anudatta and so by sutra 1.3.12 they would have been invariably atmanepadi, this aphorism makes them optionally so in the aorist. Thus अद्युतत् or अद्योतिष्ठ he shone. In other tenses than the aorist (लुङ्) these verbs are invariably Atmanepadi. As द्योतते he shines.
For a list of Dyutadi verbs see Dhatupatha.,