We also have also similar kind of thing here .where the base page has a pie chart and then the popup also has the same chart with the exact details and some description tables.
we get all the details for popup in DS flow in base page .
once the popup page is there it triggers the same DS flow[or just retrieves the data from the association both worked second being fast].
i think the trick is to check why DS microflow is not triggering again.
how is this popup page build? Is it directly calling the DS or is it inside a dataview? If inside a dataview, are you sure there is an object passed to the page?