As per Manusmriti, people from lower caste women are tainted. For example, in 10.8, 10.67-68
From the Brāhmaṇa on a Vaiśya maiden is born the ‘Ambaṣṭha’ and on a Śūdra maiden the ‘Niṣāda,’ who is called ‘Pārośora.’
‘one born to an Ārya from a Non-Ārya woman may be an Ārya in quality; but one born to a Non-ārya even from an Ārya woman is always Non-Ārya’.... The settled law is that both these are unfit for the sacraments
But in Vedas children of Asuras and Shudras (eg Trisoka in Tandya Brahmana 14.6.6, Jaiminiya Brahmana 3.234) get sacraments and are declared Brahmin and even the most preferred Brahmins by Hindu Gods like Agni and Saraswati.
So obviously Manusmriti is a totally anti-Vedic scripture here... but where does it say caste is based on father irrespective of mother's caste? Please give example from sacred scripture like Vedas, Puranas, Itihasa and Tantra.
Or are these examples of pure varna change?