Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) used to recite this verse in this way: 'bal 'ajibtu wa yaskharun' (with a dammah on the ta', meaning: "Rather, I marvelled, while they mock") [Surah al-Saffat: 12].
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8657