It appears that Lewandowski possibly did pull Fields back, but she certainly wasn't "violated" as she said on ABC. Moreover, this wasn't a violent "assault" as many in the media reported; she wasn't "dragged to the ground" as Ben Shapiro implied on Fox; and she wasn't "thrown down" as Ben Terris said in the audio recording. They're all liars.
And Lewandowski barely acknowledged Fields, so naturally he wouldn't have remembered her. He was clearly just trying to get around some intrusive reporter who was in Trump's way.