riʾāʾa ‒ sometimes like this; sometimes like that

Already Otto Pretzl had noticed that in Gizeh1924 riʾāʾa was not written the same at the three places it occurs ‒ without the authorities pre­scrib­ing that.
Iranians and UT2-KFC have the first hamza always after the tooth.
Muṣḥaf al-Azhar aš-Šarīf (Cairo 1978‒1986?) has it always on the tooth:

The others have it sometimes on, sometimes after the tooth.
In 2:264 it is normally on the tooth, except UT2-KFC and Iran.
In 4:38 it is normally after the tooth, except Taj-KFC ‒ probably changed in the next edition (1440h. it is still on the tooth).
In 8:47 all have it after the tooth except Muṣḥaf al-Azhar aš-Šarīf.