In the movies she actually was, though I think only because of Veritaserum, which makes it really not her fault (besides not having the suspicion to give the drink to umbrigdes plants instead of drinking, like Harry in the books).

In that context the break between them gives a bad look on Harry. Like "My nearly girlfriend got druged and interrogated. Such a snitch for telling them about us!" And movie Harry didn't think about what that experience was like for Cho.

Hence why it would be difficult to get this wrong. Unless one only watched the movies and didn't read the books :)