Apastambasmriti 9.23

9.23

brahmaudane ca śrāddhe ca sīmantonnayane tathā
annaśrāddhe mṛtaśrāddhe bhuktvā cāndrāyaṇaṃ caret

At a boiled-rice offering for Brahmins, at an ancestral offering, likewise at the parting-of-the-hair rite, / and having eaten at a grain ancestral offering or an ancestral offering for the recently deceased, he should perform a cāndrāyaṇa penance.