Passivisation
I found this dialogue in my book :

가 : 신발이 더러워졌네요.
나 : 네. 아침에 버스 안에서 옆 사람에게 발을 밟혔어요.

Shouldn't it be 발이 밟혔어요? My teacher says that what's written in the book is not a mistake..

Question

Passivisation
I found this dialogue in my book :

가 : 신발이 더러워졌네요.
나 : 네. 아침에 버스 안에서 옆 사람에게 발을 밟혔어요.

Shouldn't it be 발이 밟혔어요? My teacher says that what's written in the book is not a mistake..

Answer

Both 발이 밟혔어요 and 발을 밟혔어요 are correct.

(제) 발이 밟혔어요 means "My foot was stepped"
(저는) 발을 밟혔어요 means "I had my foot stepped/Somebody stepped on my foot."

Another example,
나는 그에게 손을 잡혔다.
He grabbed me by the hand.