al-Asma’ee said,

تعلموا النحو فان بني اسرائيل كفروا بكلمة واحدة كانت مشددة فخففوها قال الله: يا عيسى اني ولدتك. فقرءوا: يا عيسى اني ولدتك. مخففا فكفروا

“Learn grammar for surely Bani Israa’eel disbelieved due to one word that [originally] contained a shaddah but then they removed it. Allah said,

‘O ‘Esaa indeed I brought you into existence [wal-lad-tuka]’

And they recited it as,

‘O ‘Esaa indeed I begot you [wa-lad-tuka]’

They removed the shaddah [on the laam] and disbelieved due to that.”

Source: Rawdatul ‘Uqalaa p. 222