Question About Vegetables Snippet in BBC WIBN Doc

[mammy blue]

In the fairly recent BBC Beach Boys documentary "Wouldn't It Be Nice", during the Smile section, right after Van Dyke says "they create an image that I find appealing"... There is an interesting snippet of Vegetables played while the BB are seen running through a field. A weird tape effect blends right into the BB backing vocals. It sounds great, but I've never heard this in any Vegetables mix I've ever heard. For those who know what I'm talking about or can check it out, what's the deal with this? Does this come from a bootleg or some other source? Will it be on the box set? Thanks for your help.