What's your philosophy on a push from behind on an airborne(layup) shooter?

[Dad]

I've never had an issue making the call, but went to go help out at a camp since we had a few 1st year officials going. A1 went for a layup and B1 pushed her in the back. First year official came up with an intentional foul and one of the partners on the floor said no that's wrong just go with a regular foul. I was talking with the two clinicians on the game who were both good, one was D1 and the other a primarily D2 guy. One said call it since by book it has to be intentional and the other said the player never really pushed and just put her hands there so go with a foul.

In short, I know how I would call it, but the 1st years were confused on what to do with the play. Mainly just looking for people's thought process on this sort of play where there is a borderline intentional foul. If you don't think it's borderline that's fine. Just don't answer with something like, "Go with your judgement."