Help needed with Extract Structured Data inconsistency

I have a script that is trying to enumerate through a couple of pages of data. The page navigator has a Left, page number and right control for navigation. Currently there are two pages of data, each page has 8 rows. I have the NextLinkSelector set to a selector that seems to work - I can see it navigates to the next page, however it does wait there for perhaps 20 or so seconds before continuing. MaxNumberOfResults is 100. When I run it, the first time I can see it navigates to the second page, waits 20-30 seconds then proceeds, but the ExtractDataTable variable has only 8 rows in it. I stop the process, then run it again and it will get all 16 rows after paging to the second page and again waiting for 20-30 seconds.

I can reliably get it to return only the first page’s rows on the first run, then both on the second, then 8 on the third, then 16, and so on. Why is this? I can see the page is fully loaded before the code moves on.