Ibn ʿUyaynah did not fabricate anything.

Al-Shāfiʿī was asked about Ibn ʿUyaynah’s construal and replied, “We are more knowledgeable about this. Had the Prophet—may Allah bless him and grant him peace—meant ‘to do without,’ he would have said: ‘Whoever does not dispense with,’ but he said yataghannā; therefore we know that what he intended was taghannī.”

Al-Ṭabarī said, “What is familiar to us in Arabic usage is that taghannī is simply singing: beautifying the voice with modulation. The poet said:

Chant your verses, whatever you may be reciting;
for singing such poetry is training ground indeed.

“As for the claim of one who alleges that taghannaytu means istaghnaytu (‘I became independent’), such a usage is unknown in Arab speech and poetry, nor do we know of any scholar who has upheld it. With regard to his citing the verse of al-Aʿshā—

‘I was a man for a while in Iraq,
chaste in my conduct, long in taghan,’—

and his assertion that the poet meant istighnāʾ, that is a mistake. Al-Aʿshā here meant ‘residence,’ in keeping with the Arab idiom, ‘So-and-so ghaniya in such-and-such a place,’ meaning he settled there. From this comes the Almighty’s words, “as though they had never dwelt therein.”[1]

His further citation of the line,

‘And once we die our taghāniyā is even greater,’

is likewise misplaced, for taghāniyā is a reciprocal form that applies to two parties when each becomes independent of the other—just as one says taḍārabā (“the two men struck each other”) when each struck his companion. Whoever employs this form for an action involving two cannot use it for a single agent; hence it is impermissible to say, ‘Zayd taghānā’ or ‘ʿAmr taḍāraba,’ and by the same token one may not render taghannā with the sense of istaghnā.

I say: Al-Ṭabarī’s assertion that taghannā is never used in the sense of istighnāʾ is contradicted by the lexicographers al-Jawharī and al-Harawī, who both record it. As for his claim that the pattern fāʿala applies only to actions involving two parties, it is in fact used for a single agent in many places; among them Ibn ʿUmar’s statement, “On that day I had almost reached puberty,” and familiar expressions such as the Arabs’ saying, “I patched (ṭāraqt) the sandal,” “I punished (ʿāqabtu) the thief,” or “I treated (dāwaytu) the sick.” Taghānā can therefore belong to this class.

Accordingly, if the Prophet’s—peace and blessings be upon him—word yataghannā can plausibly mean either ‘singing’ or ‘dispensing with,’ there is no inherent reason to prefer one over the other. Indeed, if we possessed no further evidence, construing it to mean ‘dispensing with’ would be the stronger view, because it is transmitted from …

[1] Q 7:92 (and similarly Q 11:68): “…as though they had never dwelt therein.”