This is a bit convoluted; so hopefully it makes sense:
I have a parent entity: Event. Event has a Paragraph field on it: Sessions (paragraph type: Session).
I use Layout Builder to format the Full Content view mode of the Event. In the layout I add a (paragraph) view which lists the Session paragraphs as Teasers (view mode of Session) with a contextual filter of Paragraph: Parent ID. This all works as expected.
Next I set the Session teaser view mode to use Layout Builder. Set up a LB section and add a couple of the Paragraph's fields. This also works as expected. Which means through all of this, Layout Builder knows which paragraph it should be displaying fields for. Excellent.
Next (and finally) I create another View (paragraph) to create a formatted list of some of my Paragraph fields. I set the contextual filter to Paragraph ID. When I preview by entering the PID of one of my Sessions, this works as expected. When I add this view to my Session layout, of course, on my Event page, the View has no results. This is sad but expected as there is no way that Layout Builder could have passed the paragraph ID to the View - even though LB does know which paragraph to use to display individual paragraph fields.
Is this possible? Is there some trick i have missed which allows the "Session fields" view to know which paragraph it is for? Although I think this is a stretch; it does seem like not that far off from I knowing which field to display.