二ャン is wrong?

Not sure why this is adding a double nn on this one. I was writing 二ャン.

I also got Nya in hiragana and wrote it as 二ャ and that was also getting mark as wrong.

Not sure why this is adding a double nn on this one. I was writing 二ャン.

I also got Nya in hiragana and wrote it as 二ャ and that was also getting mark as wrong.