The Dabuyids ruled Tabaristan in Northern Iran in the 7th and 8th centuries. They minted this coin in the 720s-40s, after the Marwanid Reforms. However, they retained the Sasanian style and Middle Persian inscription “May his xwarrah increase.”
Then, when the ‘Abbasids took over Tabaristan, they continue to mint coins in this style, but add some Arabic. In the 770s and 780s–nearly a century after the Marwanid Reforms!
Obverse, in field: Sasanian-type bust facing right after the style of Khosrow II, to left downwards in Pahlavi: “may his kingship increase,” to right downwards in Pahlavi: AUMR BNAALA; in margin in Arabic: ‘Umar b. al-‘Ala [‘Abbasid governor]. Reverse: 125 of the post-Yazdigird III era = 160 H (776-777 CE), Tabaristan, in Pahlavi.
See also the Sasanian-style coins minted under the Tahirids.
These coins were minted in the 7th century by Georgian princes, outside of the reach of Umayyad power. The coins show the Sasanian emperor Hormizd and include his name in Pahlavi script. But the fire altar has been replaced by a cross. There are several other issues of this type of coin, some with Georgian on them, too. You can read about them here.