What prompted this woman's question and the disciple's concern ?

She was a Samaritian , and Jews had no dealings with Samaritans.
{ John 8:48 }

But evidently there was also another reason for concern.
At that time rabbinic tradition discouraged men from talking to women in public."
Yet, Jesus openly preached to this sincere woman, even revealing to her that he was the Messiah.
{ John 4:25,26}

Jesus therefore showed he would not be bound by unscriptural traditions, including thoses that degraded women.
{ Mark 7:9-13}

On the contrary,
by what he did and by what he taught, Jesus demonstrated that women should be treated with honor and respect.